Talk:United States roads tagging

Pardon my ignorance, I'm brand new to OSM, but what does one do with a road that has both a street name (e.g. Prospect Street) and a highway designation (State Highway 237)? Which designation gets the name tag? What about a road that is designated by two different highway designations (e.g. US Highway 12 and State Highway 402)?

I propose that the route designation should only be in the name when there is no name and only one route. --Korea 14:21, 15 August 2007 (BST)

We need to redirect to a standardized procedure page for US roads, and if we don't have a standard procedure for U.S. roads we need to set one up. Translating toll ways, interstate, state, limited access roads, onramps etcetera into the European naming standard is not quite intuitive for me--RobKeely 21:12, 8 November 2007 (UTC).

See this page: Talk:Highway tag usage and this page: Roads. It would be neat if all this information and opinion was more standardized and consolidated in one place. --RobKeely 21:17, 8 November 2007 (UTC)

Using Relations

I propose that we standardize a tagging scheme for numbered routes in the United States using relations. I have been doing this in Vermont if anyone cares to take a look at the data. Each route will have a relation with the following tags:

type: route

route: road

network: (Interstate, US, State, or other such as county)

ref: the route number

Then any way that is a part of the route will be made a member of the relation. With this system ways can easily be members of multiple relations in places where several route are concurrent. Mapnik doesn't yet render route badges based on relations, but we need to be forward thinking. With this system we don't have to think about whether Interstate 95 should be tagged as ref: I-95 or ref:I 95. It's simply "network: Interstate, ref: 95". The renderers can then display this data as I-95 in a generic badge or as Interstate 95 or as 95 in an interstate shield. The point is that the data is flexible. I think we should make this the standard tagging scheme for all numbered routes in the US.

--Ezekielf 23 December 2008

My concern as a resident of New Jersey is also how secondary and county routes get tagged in this fashion. Some states, such as Montana, Texas, and Tennessee, have two or more separate classes of road (in Tennessee, one highway can be of both classes on different stretches), and others, primarily New Jersey, New York, California, Alabama, and Florida, rely heavily on county highways. In Florida and New Jersey, there are county roads that receive numbers irrespective of the county they are located in and that are determined by the state highway department (in Florida, these numbers correspond to the state highway system; in New Jersey, these are three-digit numbers beginning with 5) as well as county roads with numbers assigned by the county itself (in New Jersey, these are usually three-digit numbers starting with 6 or 7). Considering these issues I've proposed a set of tags that would apply in situations like this.

This would apply to County Route 527 in New Jersey, which runs from Toms River to Passaic, using "c_nj_500" as a 500 Series Route identifier:

• key="type" value="route"
• key="route" value="road"
• key="state" value="NJ"
• key="network" value="c_nj_500"
• key="ref" value="527"

This would apply to either road in Ocean County, New Jersey designated as County Route 549 Spur:

• key="type" value="route"
• key="route" value="road"
• key="state" value="NJ"
• key="network" value="c_nj_500"
• key="ref" value="549"
• key="banner" value="spur"

This would apply to County Route 609 in Essex County, New Jersey, using "c" as a county road identifier (this model can be used for any other county road not coordinated outside the county):

• key="type" value="route"
• key="route" value="road"
• key="state" value="NJ"
• key="network" value="c"
• key="county" value="Essex"
• key ="ref" value="609"

This would apply to the Florida grid county road 884:

• key="type" value="route"
• key="route" value="road"
• key="state" value="FL"
• key="network" value="c_fl"
• key="ref" value="884"

This would apply to Montana Secondary 223:

• key="type" value="route"
• key="route" value="road"
• key="state" value="MT"
• key="network" value="secondary"
• key="ref" value="223"

This would apply to Tennessee Route 2, when demoted to secondary (multiple relations will be needed to cover the entire route):

• key="type" value="route"
• key="route" value="road"
• key="state" value="TN"
• key="network" value="secondary"
• key="ref" value="2"

CrystalWalrein 00:40, 25 December 2008 (UTC)

Vanity Names

I would strongly urge against applying names to the route relation unless the apply to the entire route. For instance, on the United States West Coast, US Route 101 runs from northern Washington State to Los Angeles. To me, it seems like this entire route should be a single relation. Portions of the route may have vanity names. For instance, the section of US 101 from San Francisco to San Jose is known as the Bayshore Freeway, and other sections are known as the Santa Ana Freeway, the Hollywood Freeway, the Ventura Freeway, and so on. -- Icycle 06:46, 24 December 2008 (UTC)

That would seem to call for either (a) separate relations for each section (e.g. name="Bayshore Freeway") overlapping with the US 101 relation (network=US; number=101; ref="US 101") or (b) just naming the underlying ways. (a) would make sense for longer routes or examples like the Hollywood (I think) which is part US 101 and part CA something-or-other or the Arroyo Seco which switches from I-110 to US:CA 110; (b) would make sense for shorter routes. Lordsutch 05:46, 24 December 2008 (UTC)

Improving tag names and values

I am not a big fan of some of the proposed tag names and values.

• The word 'state' has many meanings (status? U.S. state?) which might lead to somebody misusing that tag. Perhaps 'status' would be better, but that may have its own problems (a proposed route? or status as mapped in OSM?).
• The description for 'modifier' calls it a banner. Why not just use 'banner'? I think these routes are more commonly referred to as 'bannered' -- see wikipedia:List of bannered U.S. Routes for example.
• Why are the values for 'modifier' and 'state' in all caps? Nearly every other tag uses a lowercase string for its possible values.
• What is the purpose of 'state_id'? If this is only to distinguish two different routes with the same ref, then there should be a better way of doing so while avoiding putting multiple values in one key. See the comments for Proposed features/Value separator for why this is a bad idea. I am in favor of splitting a relation once it enters a different state, then using the addr:state tag or similar on each relation. This has the advantage of allowing us to use different symbol URLs for states that use a different style for their route markers (I'm looking at you, California).
• 'network' has at least two meanings as described in Proposed Features/Key:network. We should add the results of that proposal to this one.

--Elyk 01:35, 30 April 2009 (UTC)

A lot of these tag names are based on common practice in other parts of the world, particularly Europe. For example, Relation:route suggests the values proposed, alternate, temporary, and connection for state. (There is some overlap with the concept of banners.) Note that Potlatch and other editors support state already. I would prefer status to state, but the former is already in wide use, as far as I can tell. "Banner" is obviously the preferred term in the U.S., but I don't know if it is elsewhere. Other examples of non-American usage in OSM include "motorway" and "cycleway".

I would also be in favor of using addr:state instead of state_id, because it'd then be compatible with the Karlsruhe Schema. (I currently tag both ways, just in case.) Note that the primary reason we're putting states in here at all is for auxiliary Interstates: I-275 is a highway in Florida, but it's also a loop highway that runs through Ohio, Kentucky, and Indiana. The latter is one route, not three, and I think we should try to keep a route unified under a single relation as much as possible. (Because of the 0.6 API's restrictions, that won't be possible for long-haul Interstates, but it works for loops and spurs.)

Imagine an OSM routing engine that tries to optimize for simple directions (as opposed to CloudMade's current options, "fastest" and "shortest"). In places like the Northeast, the engine should prefer the Interstate to a Massachusetts state route, Rhode Island state route, and Connecticut state route. But if we split up the Interstate, it'll be three routes too, and the engine won't view it as being any simpler.

It'd be nice if we could keep network for identifying an individual network of routes, like I for Interstate – "Regional" really isn't a network – and describe the networks themselves in a superrelation. Unfortunately, Potlatch doesn't support superrelations yet.

 – Minh Nguyễn (talk, contribs) 06:09, 30 April 2009 (UTC)

I am not in favor of omitting the network designation from the ref. This requires data consuming applications to know how to parse the network tag in order to display something sensible. They would need to know that a highway tagged with network=US:MI, ref=14 should be called "M 14". I believe it is more reliable if the network designation is included in the ref tag. Then, applications that don't care can just use the ref tag and applications that do care can parse it to extract the number. And they can be taught to treat "M 14", "M-14" and "M14" the same way. This is consistent with the use of the ref tag as they have been used om ways for a long time and it is also how things are done in UK, France, Germany and other places. --Mjulius 21:05, 6 January 2010 (UTC)

dashes

It seems to me that using dashes in between the designator and number is more common. See

http://maps.google.com/maps?f=q&hl=en&q=san+to+lax

For an example of it used on interstates and state highways.

Can anyone describe the rationale for using a space instead (eg "I 5")?

People often confuse I-35 and 135, but maybe someone thought the rendering engine should put in the dash.--Korea 14:31, 15 August 2007 (BST)

Is there any more current discussion on this issue? Random832 19:59, 18 September 2008 (UTC)

There is now. I'd say that it's up to the renderer to put the dash in, if it's displaying it directly. It's more important that it be machine-interpretable, so that e.g. interstate shields may be used instead of just displaying the name. And of course a renderer which wants to display the number can always treat interstates specially and put a dash in. --Hawke 18:57, 19 September 2008 (UTC)

But why can't it be machine-interpretable with a hyphen so it looks good in simple renderers?

What does Mapnik do, currently? I know it's sometimes interpreting name tags to put boxes in on interstates. Random832 18:42, 22 September 2008 (UTC)

Because it only looks good with Interstates. US-10, US:WI-66, CTH-HH don't look good with a hyphen. (US:WI-66 doesn't look good with or without a hyphen, really.) Mapnik just puts the ref in a box, as far as I know, with no interpretation of the name. --Hawke 20:07, 22 September 2008 (UTC)

I haven't seen any renderers that interpret the designation at all. If it is established as a standard that in the US that a dash is used, then it looks good in renderers and is what I've noticed as is being used anyway in the US edits. — Val42 02:58, 10 June 2009 (UTC)

states

Why 3 letters for the states instead of postal abbreviations? --Korea 14:28, 15 August 2007 (BST)

Originally, the refs didn't include US: -- the three letter would be used to distinguish state highways from national highways. E.g. is CA 12 Canada 12 or California 12? Anyway, now it's US:?? two-letter style.

Because few state highways currently follow the US:ST XX format, I've changed the recommendation in the document to ST XX. CA 12 (or CA-12) should indicate California-12, not Canada-12 unless it's in Canada. A rendering engine should recognize the location of the United States and shouldn't be confused. Dufekin 19:47, 31 December 2008 (UTC)

NAK. That requires the rendering engine to know the location of the United States. --Elyk 20:11, 1 January 2009 (UTC)

Canada doesn't even have a national network comparable to that of the US, save for the Trans-Canadian Highway (which can be tagged TCH), so this shouldn't be much of an issue anyway. CrystalWalrein 14:59, 1 January 2009 (UTC)

Just because CA might not conflict between Canada and California doesn't mean that some other state abbreviation won't conflict. --Elyk 20:11, 1 January 2009 (UTC)

US:

Will the "US:" be omitted on rendering engines? Random832 19:59, 18 September 2008 (UTC)

It depends on the rendering engine, presumably. No current renderers do anything special. --Hawke 18:57, 19 September 2008 (UTC)

Experimental highway shield rendering with Mapnik2 [1] The "US:" helps to select the right shield graphic.

Alternate routes

It's not a good idea to have ALT/BUS/CITY, etc. encoded into the "ref" tag. Those attributes should go into a separate tag(s) (especially toll) instead of overloading the ref tag and requiring more string parsing by the data consumers. --SiliconFiend 01:16, 27 March 2008 (UTC)

I disagree, because you'd need to associate the tags with the values. e.g. if you have a ref=US 123;US 456+alternate_route=TEMP, it's impossible to determine whether the temp applies to US 123, US 456, or both. Plus it's useful for a very basic ref renderer like mapnik to show "US 123 BUS" instead of showing two routes with "US 123" on them. --Hawke 19:37, 15 September 2008 (UTC)

Just an observation: Hawke's objection makes sense, except where SiliconFiend said "especially toll". In the case of toll roads, the "toll" part isn't actually part of a route's designation (which might overlap with other routes) (though it sometimes appears on signs in the same place you'd find "ALT") but it's actually a property of the road itself. Tags like "toll=yes" or "fee=yes" make sense to me; do they exist already for roads, bridges, ferries, etcetera? When it comes to actual alternate routes, however, I agree with Hawke for the reasons he mentioned. Vid the Kid 14:18, 14 January 2009 (UTC)

Motorway vs Trunk: Freeway vs Expressway?

All the recommendations I've read about using the "highway=trunk" tag on this wiki have been somewhat unclear to me. The main key:highway article is absolutely useless regarding when to use "highway=trunk" in a US context, and the US-centric roads articles aren't much better. The best I can tell from United States roads tagging is that a Trunk is any road that would be a Motorway (freeway) except for a few spot deficiencies not including at-grade intersections.

It seems to me that a far more important and useful distinction is to use "highway=motorway" for all freeways and to use "highway=trunk" for all expressways. Expressways are different from freeways in that they allow a limited number of at-grade intersections. They're different from other, lower roads in that they do not allow driveway access to adjacent private properties (with a few rare exceptions). Since most expressways in the US have at-grade intersections with at least some crossroads, they wouldn't meet the "trunk" criteria set forth in this article, but in rural settings, driving on an expressway feels very much like driving on a freeway, and the speed limit is often just as high. I believe it's important and useful to mark these roads differently from ordinary surface highways on the map. Expressways are a distinct class of highway in the US (with the distinction legally spelled out in most states) and any decent map should convey that distinction. Vid the Kid 05:58, 13 January 2009 (UTC)

• My one problem is that in some areas the name 'expressway' is a matter of vanity. All Interstates around the Philadelphia area (and, by extension, most, if not all, limited access highways in Pennsylvania), for example, have 'Expressway' in their names but are still up to Interstate standard (e.g. I-76 is the Schuykill Expressway). Also, the nearby Atlantic City Expressway has no at-grade crossings whatsoever, so it fits the 'motorway' description. In fact, I've never seen 'freeway' on signs in New Jersey or Pennsylvania. CrystalWalrein 15:56, 13 January 2009 (UTC)

• • What I meant was to define "trunk" to be an expressway the way it's defined in states that make a distinction from freeways, or the way the FHWA's MUTCD defines it. Whether or not a road has "expressway" in the name isn't a factor -- since when does the ending of a road's name determine what kind of road it really is? Vid the Kid 18:16, 13 January 2009 (UTC)

You know what, I'll simplify this a bit. Rather than rely on outside definitions of an expressway, I'll just put here a table showing what I think would be the most useful distinctions between motorways, trunks, and other roads.

Property	Motorway (freeway)	Trunk (expressway)	Other roads
Access to adjacent properties	No	No	Yes
Wide clear zones (in rural areas)	Yes	Yes	Sometimes
Interchanges	Yes	Sometimes	Rarely
Divided highway	Yes	Usually	Sometimes
At-grade intersections	No	Sometimes	Usually
High Speed Limit	Yes	Yes	Sometimes

Properties in italics are the most important, defining characteristics of the road type. Rare exceptions may exist, such as National Forest roads intersecting an Interstate, or a single house located on an expressway. All of these properties (except for the speed limit) are observable from aerial photography. For the sake of this discussion, a "high" speed limit is 55MPH or higher in rural areas, or higher than surrounding streets in urban areas.

This seems to me a good definition of an expressway / trunk highway. It matches the definition of "expressway" in states that define it differently from "freeway". More importantly, it includes a significant mileage of roads in the US which are of a distinctly better grade than roads with no access control, yet aren't freeways because they have some at-grade crossings. Vid the Kid 00:29, 15 January 2009 (UTC)

Thumbs up from me! Not sure about the "usually" divided on trunk though -- IMO if it's not divided, it shouldn't be tagged as trunk. --Hawke 18:02, 15 January 2009 (UTC)

Like the idea, actually. I'm a little iffy on the restriction on adjacent properties, since the prohibition in the table might not carry well in states with high populstion densities or several urban areas. In rural areas I don't see a big issue, but I would like to see considerations for California or the Eastern Seaboard. CrystalWalrein 22:44, 15 January 2009 (UTC)

But driveway access is exactly what sets these highways apart from other roads, especially in built-up areas. And yes, such roads do exist in built-up areas. Examples include: the M-5 north of I-696 in Novi, Michgan; Texas Highway 99 south of the Westpark Tollway on the outskirts of Houston; US-1 (MLKJ Pkwy / 20th St Expwy) between I-95 and US-23 in Jacksonville, FL; Route 2 between I-95 and Route 27 near Concord, Massachusetts; US-60 between I-17 and Loop 101 in Phoenix, AZ; and the Alton Parkway through Irvine, CA. (Those six examples were found with a quick look at Google maps and aerial imagery of just 8 or 9 cities I looked in.) These roads have no (or extremely limited) access to adjacent properties because the DOTs prohibit it, and that is what makes it an expressway (or, in this case, trunk.) Vid the Kid 15:19, 17 January 2009 (UTC)

Hmm, how would population density matter? Isn't it simply be the case that highway=trunk by the definition above is rare in densely-populated areas? No matter how dense the population is, if there are (many) driveways entering on to the road, it's not a trunk road. --Hawke 23:58, 15 January 2009 (UTC)

Then explain how the A2, A3, and A24 in southeast London receive trunk classification and they have rows of homes with access right from the road itself. I understand that this comes down to government classification, but I still consider it unfair to not extend similar situations, where the aforementioned roads are major distributor roads in the area and they've historically had property along the way, to areas of the United States that face similar situations, especially in New Jersey where I map.

My point is that I do not consider it fair to restrict the trunk tag to roads crossing empty swaths of land while it's better used to define the best route for commercial traffic where motorway access isn't readily available. CrystalWalrein 05:55, 16 January 2009 (UTC)

Expressways aren't exclusively found in rural areas, as I pointed out above. They are sometimes (though not often) found in built-up areas as well. In those cases, such a road most likely is "the best route for commercial traffic where motorway access isn't readily available" because of its limited-access status. Anyway, the usage of the "trunk" tag within urban areas may be restricted – but it's restricted by the circumstances of the roads, not the definition of "trunk". That's not unfair, it's accurate mapping. (Besides, the definition of "trunk" already in this article is even more narrow and more likely to exclude urban areas. Adopting my definition of "trunk" for the US would increase its usage in both urban and rural environments.) Vid the Kid 15:19, 17 January 2009 (UTC)

I'd also like to point out that many expressways are upgraded to freeways when urban development reaches them. That is, if the DOT determines full access control and grade separation is warranted, and the funding is available, then at-grade intersections are replaced by overpasses or interchanges, or the crossroads simply cut off. Vid the Kid 15:23, 17 January 2009 (UTC)

I agree that the definition of trunk as currently given on this page is much too restrictive. The closest equivalent to the UK in terms of density (and thus most suited to the current renderings on OSM) would be to define trunk much as "primary" is defined on this page. But since the UK map arguably has too much green (too few distinctions among major roads), I think an intermediate approach is appropriate.

I've edited Key:highway with my impression of how things are being tagged at present (at least in the Western US), which I think is reasonable. By this guideline, major routes useful for planning interstate trips should be tagged as trunk. These are the major trucking routes, which often have substantial sections that are built to freeway standards, and which otherwise would result in disembodied blue bits when the map is zoomed to only show trunk and interstate routes. My approach seems to differ from the proposal above on a few points, which reflects a differing focus on form vs. function. While I agree that a trunk route should generally be one that is built to "true expressway" standards in urban or suburban areas, this does not map to rural areas, where driveways are less frequent and providing alternate access to properties more expensive. In rural areas, particularly mountainous ones, moving earth and purchasing right-of-way for frontage roads is a substantial cost in building freeways or expressways without driveways. It is more common to build divided roads with (occasional, perhaps every 1/4 mile or so) driveway access than undivided roads without.

Additionally, roads I would consider trunk class occasionally have reduced speed limits as well, but somewhat rarely. If the town they pass through is big enough to pose a significant delay to motorists, there will likely be a bypass. US 101 south of Eureka is a good example: it is largely freeway and divided highway, but has a reduced speed limit in Hopland, Laytonville, and through Richardson Grove. It even has stoplights through Willits. Despite this, the road is the only reasonable way to get to a huge chunk of the state from points south (and a bypass of Willits has been planned for ages). Some other roads that meet my criterion may have even fewer freeway/expressway sections, e.g. US 101 and US 199 joining Eureka to Oregon.

(As another rough guideline, I've been using "should receive the most prominent color/style on a (paper) US map" and "should be included on a US map" as rough criteria for trunk and primary respectively.) --Speight 06:07, 12 February 2009 (UTC)

I know I am a bit late to the discussion, but I think the motorway tag should always be applied to interstates, as it is the equivalent to the motorway in the US, that being the national system of roads (us routes are different), whether completely up to standards or not. If an interstate has a toll, like I-76 in Pennsylvania, it is still an interstate, and therefore should still be classified as a motorway. Also any interstates on paper should be as well, like the ones in Hawaii and Alaska. Northern Pyro (talk) 07:13, 22 April 2014 (UTC)

Directions

This page suggests using separate relations for each change in direction, and for each side of a separated highway. Wouldn't it be easier to keep the entire route in one relation, using roles to distinguish each direction? – Minh Nguyễn (talk, contribs) 23:20, 1 February 2009 (UTC)

Sometimes a single route will have multiple route designations, and they may be different directions. A role tag for the route would leave too much ambiguity: to which route does it apply? Separate relations for each direction provide clarity in any situation. Granack 08:08, 4 October 2009 (UTC)

See my response at Talk:Interstate Highways Relations. – Minh Nguyễn (talk, contribs) 11:56, 4 October 2009 (UTC)

Better definition of US road class

The discriptions are a little hazy and many defining road class in the US. My sugestion would be to go with a road classification that can work anywhere in the US. Lets talk about this and come to a concensus of how roads should be classified.

"This discussion was started to bring "America" together to use one type of road classing system. The US is useing multipe classing systems. There are multiple pages which all have their own opinion on how US roads should be classed. This is confusing to all users trying to class US roads."--Nickvet419 14:07, 26 February 2009 (UTC)

--List--

This list will be the base for US road classification. It is based off the US administative system already in place with minor modifications for trunk class and urban areas. Any state, or city clarifications should be noted on their apropriate page.

Motorway

• Interstate Highways
• Freeway
• A Divided highway that is entirely grade separated.

Trunk

Unless part of the "Interstate system"

• An Arterial Divided highway that is partially but not entirely grade separated.

Primary

Unless classified as "Trunk or higher"

• Interstate Business Routes
• US Routes
• US Business route
• State Routes in dense urban areas.

Secondary

Unless classified as "Primary or higher"

• State highways
• State Business route
• Some County routes, including all Wisconsin County Trunk Highways.
• Major Urban Streets = Streets in Urban areas with high amount of traffic, usually lined with businesses and controlled with traffic lights. (Often roads that cross highways and rivers)

Tertiary

Unless classified as "Secondary or higher"

• County Route
• Forest_Route
• Indian Route
• National Scenic Byway

Residential

Unless classified as "Tertiary or higher"

• Minor Roads in residential areas.

Unclassified

Unless classified as "Residential or higher"

• Minor Roads.

Service

• Alley, Driveway, Parking_aisle, other service

Track

• Generally unpaved or not maintained. Generally not a named road with no street addresses. Like a forest access road or farm road. Some driveways may also be classified like this.
• Drivable by motor vehicles, but may require an off road vehicle.
• Key:tracktype

Path

• Not for motor vehicles. Generally for walking, bike or equestrian.
• surfaces from well maintained paved to a dirt line worn in the undergrowth.

Main Discussion

Your defenitions Please put all your defenitions here

Trunk as toll discussion

There's toll=yes for toll roads so using a whole highway category just for that seems somewhat wasteful. Alv 06:20, 23 February 2009 (UTC)

There are a large amount of toll roads in the US. This page also recomends marking toll roads as Trunk. --Nickvet419 07:02, 23 February 2009 (UTC)

That's because toll roads cannot reasonably be built less than trunk (controlled access is a must for a toll road). Toll roads can also be built to interstate/motorway standards. Also, I would hardly say that there are a "large" amount of toll roads in the US. There are places where state highways are the same as "primary", places where they're the same as "secondary" and places where they're the same as "motorway" because they happen to use the same physical road. The whole thing certainly is rather hazy, but that's at least partly because the british primary/secondary/tertiary system doesn't map perfectly to the US system. You may wish to look at this proposal for separating the purely physical aspects from the purely administrative. --Hawke 18:55, 23 February 2009 (UTC)

It also says freeways are marked motorway unless they have toll or other obstructions. That makes any interstate toll a Trunk tag according to this page.-- Nickvet419 20:58, 23 February 2009 (UTC)

So it does. But saying "the only thing that can be marked trunk is a toll road" goes too far. --Hawke 21:18, 23 February 2009 (UTC)

I'm strongly against making tolls be the sole reason a road isn't marked as motorway, if it meets the other standards. You can go hundreds of miles on a ticket-based tollway without having to stop for tolls, and the newer electronic-only and/or pay-by-mail toll roads in Texas make it impossible to stop to pay a toll. There is also precident in OSM for toll motorways, like the M6 Toll near Birmingham, UK. Djlynch 00:35, 26 February 2009 (UTC)

I have seen many maps that use a green line to represent a toll road. Please do not assume that a trunk road, which happens to be rendered as a green line by Mapnik or Osmarender, represents a toll road.--Elyk 06:22, 25 February 2009 (UTC)

This was done because Trunk tag dosen't nessisarily fit into the US road system. It can be usefull to discribe it as a toll or obstructed way. --Nickvet419 06:31, 25 February 2009 (UTC)

From the European perspective the guidelines at Roads#USA appear appropriate and best fitting out of the various different schemes on various pages. And those do have solid-enough criteria for using trunk. Alv 06:51, 25 February 2009 (UTC)

According to Roads#USA, where would you differ between a seporated Trunk and a seporated Primary?--Nickvet419 07:07, 25 February 2009 (UTC)

Sometimes it would require local judgement but IMO there are some properties that allow a trunk status and some that hint at the road being a primary. Given any separated carriageway road (that's not a motorway) linking cities: if the speed limit is high and it's missing only one design criteria for a motorway, it's a trunk. If the speed limit is lower than on the trunk roads and/or it's missing several design criteria for a motorway, it'd better be a primary. Also, if that road is not a connection from the city it is in to a neighboring city, it's unlikely to be higher than primary. A road can change from trunk to primary as it enters an urban area and loses some of the characteristics that make it a trunk outside that area - although very short isolated sections of otherwise trunk roads (two miles at most, I'd say) through smaller villages could still be trunk even when there are lower limits or intersections with traffic signals, if it's the only obvious route through the village. The opposite is also possible: a road can start as a trunk from a city (or run through) but fade to a primary if it crosses and connects to a proper motorway for intercity travel. Alv 09:43, 25 February 2009 (UTC)

Tht would work fine if the US didn't use a grid layout. Most US cities connect to other cities using US and State Highways using the grid network. --Nickvet419 11:33, 25 February 2009 (UTC)

Would it make a difference to say "linking major cities"? Alv 12:29, 25 February 2009 (UTC)

It would make a diference to say its a devided highway without the explicit use of grade seporation and exit ramps.--Nickvet419 17:35, 25 February 2009 (UTC)

So now we've accounted for toll roads -- what about primary/secondary/tertiary? Some county roads are physically indistinguishable from some US highways[2], yet you put them two levels lower? Similarly, some state and US roads are indistinguishable from interstates [3] yet they're lower on your scale. highway=* is meant to describe a physical, not an administrative designation, and the two don't really correspond very well. --Hawke 22:12, 23 February 2009 (UTC)

I think it should be marked in an administrative hiarchy. IE toll roads can be taged Trunk and no lower. US Intertate highways marked Motorway and no lower. US/State Routes marked Primary and no lower. This way thay can be a higher catigory if following the same route as a higher catagory. Also this would cut out any guess work, easy to understand and follow.-- Nickvet419 04:30, 24 February 2009 (UTC)

So this is what you're getting at:

Motorway Any road built to Interstate standards that is maintained by the state transport department without the use of a satellite agency (e.g. the Pennsylvania Turnpike Commission) and carries an Interstate designation — can apply to US 50/US 301 in Maryland as it is recognised by AASHTO as I-595, or I-80 Business in California as AASHTO (but not Caltrans) calls it I-380, or Alaska Highway 1 from Anchorage to Matanuska

Trunk Any road with controlled access that either is an improved state or US highway, any toll road, or a controlled-access road not directly maintained by the state transport department — affects all segments of the Pennsylvania Turnpike, the New Jersey Turnpike, Ohio Turnpike, Kansas Turnpike, Indiana Toll Road, and all Illinois toll roads, even though most are Interstate highways (many of which are important cross-country routes); can affect long bridges on Interstate segments that must be maintained through tolls (such as the Delaware Memorial Bridge, Sunshine Skyway Bridge, and the San Francisco-Oakland Bay Bridge); does not reflect the M6 Toll in the UK, or the French autoroutes or Italian autostrade

Primary All US and state highways — some have been demoted or turned over to the county, such as former New Jersey Route 24, and some are locally maintained but carry a state designation (e.g. New Jersey Route 347)

Secondary Secondary roads — can extend to Tennessee Secondary Routes, Florida gridded county routes, or New Jersey 500 Series Routes

Tertiary All other general thoroughfares — can apply to individually assigned county routes

Would that be more accurate? CrystalWalrein 03:57, 24 February 2009 (UTC)

Thats what were trying to figure out, but lets take this one step at a time.-- Nickvet419 04:26, 24 February 2009 (UTC)

There are good reasons to make a distinction between US highways and state highways. For that reason I think we should reserve primary for US highways and secondary for state highways. tertiary should be used for county highways and major streets. Butlerm 19:39, 6 April 2009 (UTC)

I don't think tertiary should have two meanings. It should be either county highways (my preference) or major streets. --Hawke 19:43, 6 April 2009 (UTC)

Would this apply to bridges, such as the San Francisco-Oakland Bay Bridge, that require a toll to cross, even if they are maintained by the state highway department and carry an Interstate designation? And would this affect roads that have the option of continuing through a toll at freeway speed (such as Express EZPass or E-Pass Express Lanes in Orlando)? CrystalWalrein 02:41, 25 February 2009 (UTC)

I would think yes, any paid access road. This would trump lower classifications.--Nickvet419 05:45, 25 February 2009 (UTC)

Frankly I think toll roads should be classified as motorway if they have full control of access (e.g. all access at interchanges or termini), and lower otherwise. The lack of trunks in the US is because the Tiger import didn't bring in any trunks (because TIGER doesn't classify that way), not because there aren't routes worthy of OSM-wide trunk status. We should stick to OSM-wide criteria, and toll booths don't count as the sorts of "obstructions" that demote from motorway in other countries - otherwise most of France's autoroutes would be trunk instead of motorway. Lordsutch 00:21, 26 February 2009 (UTC)

Thats why this list was set up with Trunk as a higher catagory, to illustrate toll roads. The other standard I think could be apropriate is Trunk = seporated roadways that act as expressways that are not explixit to grade seporation or exit ramps. for example, this would include Skokie highway that runs nort of I94, Lake Shore Drive that runs along the, and cline ave in Gary.--Nickvet419 03:23, 26 February 2009 (UTC)

Motorway Dicussion

do we want to use the word entirely? example [4] lakeshore drive in chicago. south from Roosevelt to 57th, it could be classified as a motorway, but the road is not entirely grade seporated north of Roosevelt.-- Nickvet419 19:21, 24 February 2009 (UTC)

that example has intersections and it appears even pedestrian crossings. Definitely not a motorway IMO; Trunk is probably the lowest I'd tag it, and primary if speed limits are less than 65mph. Also, it's entirely reasonable for the road to change classifications along its length. So it could be motorway south of Roosevelt, and Trunk north of Roosevelt. --Hawke 19:52, 24 February 2009 (UTC)

Tertiary Discussion

Why are you putting secondary below tertiary? That makes no sense. You're aware that "tertiary" means "three" in the same way that "secondary" means "two", correct?

ok -- Nickvet419 07:28, 24 February 2009 (UTC)

County routes should probibly be places in Tertiary. -- Nickvet419 07:44, 24 February 2009 (UTC)

Possibly. I've found that county routes vary greatly, even within a single state and county. Some are physically the same as a primary highway, others should count as unclassified. This is the problem of trying to fit an administrative designation (county route) into what is purportedly a physical classification. --Hawke 16:56, 24 February 2009 (UTC)

I would tend to put county routes in secondary. This probably varies around the country though. --Hawke 18:16, 24 February 2009 (UTC)

because of the admin level I dont think county routes should be classified any higher, unless they follow a route or meet the discription of a higher class.-- Nickvet419 18:42, 24 February 2009 (UTC)

In my part of the country (Wisconsin), some state highways are indistinguishable from some county highways -- that is, you can't tell apart from signage which is which. Actually, that's true even for some US highways [5]. --Hawke 19:19, 24 February 2009 (UTC)

As long as we use admin levels to catagorize roads, it will need to stay in this catagory. I think this is a sound way of classing. This would then mean that primary, secondary, and tertiary all share the same atribute of being major routes. only thing that seporates them is the location, and the admin level it carries. --Nickvet419 20:21, 24 February 2009 (UTC)

That might be a point of contention: Key:highway claims to be a description of physical, not administrative characteristics. It has been mentioned elsewhere that admin_level=* might be more appropriate for this kind of thing. --Hawke 21:36, 24 February 2009 (UTC)

not everyone will go for this because many places are well defined by collored road signs, but in the US, this seem like the way to go.--Nickvet419 02:01, 25 February 2009 (UTC)

also, Looking around it seems that when the TIGER data was imported they used the admin level to class the roads, although many couny roads did not recieve a class. One issue in the US is many of the roads are designed in a grid, US/State/County roads were designed to pass though cities/towns. So this makes it hard to determine the class based on the Key=Highway page discription.--Nickvet419 06:07, 25 February 2009 (UTC)

How would 500-series county routes in New Jersey be defined here? CrystalWalrein 02:42, 25 February 2009 (UTC)

they would be in this class.--Nickvet419 06:12, 25 February 2009 (UTC)

Primary discussion

should business routes fall to the next class? -- Nickvet419 07:42, 24 February 2009 (UTC)

I would say not. The ref tag, e.g. ref=US 51 BUS should do the job. --Hawke 16:51, 24 February 2009 (UTC)

Might Interstate Business Routes be suitable for upgrading to Trunk? I've never seen one, so I don't know what they look like. --Hawke 18:14, 24 February 2009 (UTC)

There are no tolls or obstructions and most dont meet the motorway definition. They should be at least a primary road.-- Nickvet419 19:04, 24 February 2009 (UTC)

Secondary discussion

Is "Major urban roads" clearly defined anywhere? --Hawke 16:52, 24 February 2009 (UTC)

should we call them major urban streets? Every large city has there own list of Major streets. If you google "Major Streets" you can find some of these lists. We can define them more, by saying streets with high amout of traffic, usually lined with buisnesses and controled with trafic lights.-- Nickvet419 17:20, 24 February 2009 (UTC)

I don't think it matters what they're called. I'd just prefer to have a way to consistently differentiate them from any other road -- that is, a way to tell from driving along the street, "I am now on a Major Urban Street". --Hawke 18:12, 24 February 2009 (UTC)

A separate theory, Texas style

Looking at all these different examples and thought processes on highways, I would like to chime in with how most of Texas seems to be designing.

• Motorway - The highest form of highway. Restricted access, no at grade intersections (exception being I-40 through the panhandle). This includes toll routes. Examples:
  • Interstates
  • Toll Routes (See Texas SH 45 and SH 130 around Austin)
  • Some US Routes and State Highways that meet the restricted access criteria (look around the Dallas/Ft. Worth metroplex. They're all over)

• Trunk - A highway that has separated lanes for each direction, has both at grade and exit ramp connections, depending on the amount of cross traffic from crossing highways. When this type of highway bypasses a region and is built to motorway standards, it should be labeled as a motorway. When it passes through a town and loses the separation between opposite direction travel, it remains trunk. Green does not equal toll. Examples:
  • Some US Routes and State Routes (US Route 77 from south Texas to Corpus Christi, Texas SH 71 from Austin southeast to Columbus)

• Primary - A highway that is a major thoroughfare between cities that does not meet an enhanced criteria. Can be 1 lane or 2 lane each way (maybe even 3), but not separated. Now inside city limits, this type of highway would equate to a road that is 2 to 3 lanes each way, with either a curbed median in the middle or the suicide turn lanes between them. Examples:
  • All other US Routes and State Routes not promoted to Motorway or Trunk.
  • Farm to Market Roads in cities only.

• Secondary - A highway that can be a connecting route between cities, but may not be the most used route. Usually one lane each way. Examples:
  • Farm and Ranch to Market Roads outside of cities.

• Residental - A road in residential areas. Fairly self-explanatory.

• Service - alley, driveway, dirt farm roads, dirt roads.

Interstate and US Business Routes would be classified one step below the main highway that replaced it (main highway=motorway>business highway=primary, primary>secondary)

Problems - The only troubles I would have are how to categorize a coupel things. How would a 2 to 3 lane each way road separated by a grassy curbed median in a city (e.g. a parkway) be classified? Wurzbach parkway in San Antonio is mainly Trunk, but I personally would classify them Primary. How are the turnarounds under morotway bridges classified? I have been labeling them as unclassified, as any other classification needs the segment to be named, but the turnaround aren't. I also haven't found a good use for tertiary roads yet.

25or6to4 21:44, 25 February 2009 (UTC)

I think this is closer to the spirit of OSM-wide conventions. My understanding is that Wurzbach (like Loop 1604) is a mix of freeway and non-freeway sections; the freeway parts should be highway=motorway and the rest should probably be primary or trunk depending on how frequent the signals are. Lordsutch 00:18, 26 February 2009 (UTC)

+1, but I actually did a reasonable amount of the tagging that got incorporated into the plan above. I went with a system of US highway no lower than trunk, state highway no lower than primary, other roads on the state highway system (loops, spurs, farm-to-market, etc.) no lower than secondary, but I'm open to classifying US highways as primary. My philosophy within cities is that arterials which are particularly long or heavily traveled but don't meet the standards for a trunk road or motorway are primary and other major commercial streets are secondary. As far as tertiary roads go, I would define them as "city streets that have a median, more than two lanes, and/or moderate traffic, but are low speed and primarily residential, or locally-maintained rural roads that are important for local navigation, such as connecting two nearby highways." Djlynch 01:49, 26 February 2009 (UTC)

This is why i sarted up this discussion. It seems like everone has their own way of tagging. Lets contine to discuss the list and come up with a standard way that works for everyone.--Nickvet419 03:26, 26 February 2009 (UTC)

+1 as well. As for farm roads, do you mean county roads (usually on a 1-mile grid in the midwest) or agricultural roads for farmers to reach their land with a tractor or truck? I would argue that county roads should use highway=unclassified and agricultural roads use highway=track. Forest service roads are probably highway=track, forest roads of better quality that form a network and occasionally have houses along them (more like county roads) should use highway=unclassified. highway=service should be for short segments of road that are used for service only, i.e. alleys and driveways.--Elyk 05:55, 26 February 2009 (UTC)

This I agree with (I map New Jersey, the Sarasota, Florida area, and southeastern Pennsylvania). My only difference is that I use trunk to cover any road that, at the extreme least, relies on jughandles or other traffic redistribution to afford through traffic a through way; this designation (except in the case of NJ 3, NJ 21, and NJ 42) does not change for freeway-grade or urban portions of the route, but may be demoted if a road of better quality exists reasonably nearby, the road does not go to a popular destination, or the road is an unacceptable bottleneck or poses physical hazards (e.g. sharp curves or steep inclines). Basically I try to abide by rules that would determine the grade of roads in the UK (that's that the tags are based on, anyway). CrystalWalrein 03:57, 26 February 2009 (UTC)

I think as much as I would like to keep all the US Routes the same, not all are equal anymore. Otherwise I would agree state highways no lower than primary and loops/spurs no lower than secondary. I would also agree with the note farther down that Farm and Ranch to market roads in Texas would be a good tertiary route. For farm roads, I meant the mainly dirt road grids, for example, across Iowa. I thought they had the same consistency of a dirt alleyway. I had not thought about using track for anything, as I thought that would be specifically for a racetrack feature (Indianapolis 500, Texas Motor Speedway, etc...). Also, a jughandle is a new term for me. Can you give me an example? 25or6to4 23:35, 26 February 2009 (UTC)

Actually, forget what I said about trunk and refer to the New Jersey page instead (what I said here isn't accurate). A jughandle is a ramp that allows traffic to access a side road without interfering with traffic flow on the host road. A good example is the one at NJ 73 and Camden CRs 689 and 708 [6], which was formed a year ago when a roundabout was removed. Traffic headed to either Camden CR 689 or 708 from NJ 73 must leave the mainline, allowing faster traffic to proceed through the intersection. CrystalWalrein 05:36, 27 February 2009 (UTC)

From talking to many Users on this suject, The US has a admin system already in place, Interstate, US, State, County routes. They think that this is a good Standard for Classing roads in the US. If you want to further tag roads by phisical properties, you shold use the key=smoothness tag.--Nickvet419 03:40, 27 February 2009 (UTC)

True about the US admin system, but I think it frequently follows this line of classification as most Interstate, US Hwy and toll roads are limited access with no grade crossings (Motorway - Trunk). Most urban freeways are part of the US Interstate system or US hwy system. Most State Highways are not limited access and have grade crossings (Primary). Personally I like looking at a map and having the roads color coded according to how much obstructions there are (cross traffic, traffic control devices, limited lanes).--Xsintrik 03:48, 27 February 2010 (UTC)

Your farm-to-market roads would fit in the tertiary class.--Nickvet419 20:44, 26 February 2009 (UTC)

Organized tagging breakdown

There is a lot of discussion about whether to tag according to administration level or physical characteristics. It seems to me that everyone voting for administration level always includes exceptions based on physical characteristics, so why not just tag according to physical characterists? Here is my suggestion. Of course it does have a Texas bias. This is also posted on the Texas page. --Xsintrik 18:17, 1 March 2010 (UTC)

Motorway: Divided highway with 2 or more traffic lanes in each direction of travel, 55mph or greater speed limit, grade separated (no at-grade intersections), limited or controlled access through the use of entrance/exit ramps, no access from private or business driveways. Has feeder/frontage roads. Usually has shoulders or breakdown lanes. This includes US Interstate Highways, Toll roads, Freeways and State Highways as long as they are divided, limited access and grade separated.

Use these tags:

Highway=motorway

Oneway=yes

Maxspeed=number

Minspeed=number

Name=name of the motorway

Ref=reference_name

Lanes=number

Use these tags for special situations:

Highway=motorway_link for entrance and exit ramps.

Highway=motorway_junction for connections to motorway_links and add the exit number.

Bridge=yes at bridges and overpasses.

Layer=1 for the bridge segment.

Tunnel=yes at tunnels.

Motorway_link: An entrance/exit ramp to a motorway.

Use these tags:

Highway=motorway_link

Highway=motorway_junction for node connections to motorway_links and add the exit number.

Trunk: Divided highway with few at grade crossings. Usually limited access but may have a few intersections controlled by traffic signals, some private and business driveways. Does not have feeder/frontage roads. 55mph or greater speed limit, usually has shoulders or breakdown lanes. This covers US Highways and state highways.

Use these tags:

Highway=trunk

Oneway=yes

Maxspeed=number

Minspeed=number

Name=name of the trunk

Ref=reference_name

Lanes=number

Use these tags for special situations:

Highway=trunk_link for entrance and exit ramps.

Bridge=yes at bridges and overpasses.

Layer=1 for the bridge segment.

Tunnel=yes at tunnels.

Trunk_link: An entrance/exit ramp to a trunk. May be a large sweeping right turn lane from the trunk road to a lesser road that allows right turning traffic to bypass the intersection and traffic lights.

Use these tags:

Highway=trunk_link

Primary: A highway that is a main thoroughfare or links larger cities and that does not meet any higher criteria. Business route through cities. May be multi-lane and have a lot of business’. A very busy and important road. 55mph or greater speed limit except in urban areas. In rural areas probably has shoulders or breakdown lanes. This covers State Highways that don't fit a higher designation.

Use these tags:

Highway=primary

Oneway=yes if one way road

Maxspeed=number

Minspeed=number

Name=name of the road'

Ref=reference_name

Loc_name=local name - unofficial or local name for the road (a State Highway might have a local name through a small town).

Lanes=number

Use these tags for special situations:

Bridge=yes at bridges and overpasses.

Layer=1 for the bridge segment.

Tunnel=yes at tunnels.

Secondary: Urban arterials that connect to higher highway networks. Rural highways that connects smaller cities although may not be the most traveled route. Less busy than Primary with fewer business’. Blvd, Ave, most city thorough fairs, freeway feeder roads in urban areas, hard paved, striped, 2 or more lanes in each direction of travel, may or may not be divided and/or one-way, 45-55mph or greater. May or may not have shoulders. Grade crossings controlled by traffic lights with few if any stop signs.

Use these tags:

Highway=secondary

Oneway=yes if one way road

Maxspeed=number

Name=name of the road

Ref=reference_name

Loc_name=local_name - unofficial or local name for the road (a State Highway might have a local name through a small town).

Lanes=number

Use these tags for special situations:

Bridge=yes at bridges and overpasses.

Layer=1 for the bridge segment.

Tunnel=yes at tunnels.

Tertiary: Farm to Market roads and most 2 lane roads in cities – hard paved, striped, 55mph or greater (except in towns where the speed limit is reduced), may or may not have shoulders. Less busy than Secondary with fewer business’.

Use these tags:

Highway=tertiary

Oneway=yes if one way road

Maxspeed=number

Name=name of the road

Ref=reference_name

Loc_name=local_name - unofficial or local name for the road (a State Highway might have a local name through a small town).

Lanes=number

Use these tags for special situations:

Bridge=yes at bridges and overpasses.

Layer=1 for the bridge segment.

Unclassified: County Roads – hard paved or gravel, no paint stripes; rural highway feeder roads or highway u-turn lanes under an overpass. Typically 45-55mph, no shoulders.

Use these tags:

Highway=unclassified

Oneway=yes if one way road

Maxspeed=number

Name=name of the road

Ref=reference_name

Loc_name=local_name - unofficial or local name for the road (a State Highway might have a local name through a small town).

Lanes=number

Use these tags for special situations:

Bridge=yes at bridges and overpasses.

Layer=1: for the bridge segment.

Residential: Roads in Sub-divisions with close set houses, 35mph or less, has "Children at Play" signs. May also have Churches, schools or a minor business’ as well.

Use these tags:

Highway=residential

Maxspeed=number

Name=name of the road

Ref=reference_name

Service: Alley, Business Driveway, Parking Isles, Privately maintained road used by several houses or a small subdivision or trailer park - May be paved or unpaved, narrow, 45mph or less, no shoulders, not maintained by State, County or City.

Use these tags:

Highway=service

Maxspeed=number

Name=name of the road

Ref=reference_name

Use these tags for special situations:

Amenity=parking for parking areas.

Service=parking_aisle for driving lanes between parking spots.

Amenity=Fuel for a gas station.

Service=alley

Service=driveway

Private: Private drive ways and farm roads.

Use these tags:

Highway=private

Track: Used for non-public access to farm land. Not maintained or paved, no street name or addresses. Unimproved forest roads. May require off road vehicle depending on weather conditions.

Use these tags:

Highway=track

Create new toll tag?

I'm aware that toll=yes exists, but I volunteer a new tag that causes a different rendering (perhaps a darker shade of green) for toll motorways altogether, leaving other classes (trunk and lower) to primarily surface roads. CrystalWalrein 04:02, 26 February 2009 (UTC)

This is a rendering issue only. I suspect the reason for this whole discussion is about rendering. If you go look at any printed U.S. road map, colors represent administrative classifications. For example, blue == Interstate highway, green == toll road, red == U.S. highway, etc. Mapnik and Osmarender don't use the administrative classification but instead use the highway=* tag, which is intended to describe physical attributes.

I think the debate above is trying to redefine the highway tag to describe the administrative classification so that Mapnik and Osmarender generate maps where some color represents a certain administrative class. A better solution is to (1) use the route relation as proposed on the article page and (2) write some rendering rules that use the route relation's network=* and toll=yes to determine the color.--Elyk 04:36, 26 February 2009 (UTC)

This statement is not exactly true. The UK uses administrative class to mark Primary and secondary roads. This discussion was started to bring "America" together to use one type of road classing system. As I stated before the US is useing multipe classing systems. There are multiple pages which all have their own opinion on how US roads should be classed. This is confusing to all users trying to class US roads.--Nickvet419 14:03, 26 February 2009 (UTC)

In the UK I believe that the administrative class also describes the physical class (please correct me if I'm wrong), similar to how Interstate highways are all supposed to be divided and grade-separated. This is not true in the U.S. since such a designation does not imply anything about the physical attributes. I've seen state highways that are four-lane divided and I've seen U.S. routes through residential areas. I think it's important that we separate the administrative from the physical to reduce confusion when trying to figure out how to tag a road. This way we avoid corner cases like I described above.--Elyk 05:51, 27 February 2009 (UTC)

No, The UK road system is similar to the US by using Signs to classify roads. Basicly, M=motorways conecting cities, A= conecting towns, B=lower CDU= "labled for local authorities who are responsible for maintaining them". Read this [7] It states "The classification has nothing to do with the width or quality of the physical road." The US also has a system in place for admin class. "Interstate,US,State,County". Most users I've talked with think this is what we should use in the US. If we want to tag the phisical condition of the road, we can use the smoothness, speed, lanes, and other atribute tags found on the map feature page.--Nickvet419 06:23, 27 February 2009 (UTC)

Thats not a bad idea but why create a new tag?--Nickvet419 18:28, 26 February 2009 (UTC)

Decision Tree

We need an agreed-upon set of rules for choosing how to apply the tags; one that removes all thought and confusion from the process. Below is my proposed algorithm.--Elyk 06:45, 27 February 2009 (UTC)

if (has_administrative_designation):
        # If the road is part of an Interstate highway network, a U.S. highway
        # network, state highway network, etc., then create a relation (if one
        # doesn't already exist) and add the road to it.
        add_to_relation(type=route, route=road, ...)


if (toll_road):
        # Could be a toll bridge as well.
        toll = yes


if (physical_attributes_unknown):
        # This is the default for when you know nothing about the road.
        highway = road

else:
        # Do NOT depend on the administrative designation when choosing the
        # value for the highway key.  In general most roads in the same
        # network will use the same value, but not necessarily.

        # Keep this thought in mind:  If someone were to take down all of the
        # Interstate, U.S., state, and county route signs along all roads,
        # would you be able to distinguish one road as being more important
        # than another?

        if (driveway or alley):
                # Roads tagged with highway=service should be short roads used
                # for _service_ only.
                highway = service

        elif (for_agricultural_use):
                # These are paths, usually dirt or gravel, for farmers to
                # reach their land via truck or tractor.  Unimproved forest
                # service roads also fit into this category.  This does not
                # include most county roads (usually on a 1-mile grid).
                highway = track

        elif (lined_with_houses and low_speed):
                # May have the occasional business/church/school, but mostly
                # houses along one or both sides of the road.  Typically 20-30
                # MPH, maybe lower depending on the area.
                highway = residential

        elif (divided and high_speed and limited_access):
                # Typically 4+ lanes and 60+ MPH, must be limited or
                # controlled access (no intersections with service or
                # residential roads)
                if (grade_separated):
                        # Freeways.  You must use entrance/exit ramps to
                        # access the road.  All roads built to Interstate
                        # standards are motorways, but not all motorways or
                        # Interstate highways are built to Interstate
                        # standards.
                        highway = motorway
                else:
                        # Expressways.  Occasional intersections with lesser
                        # roads, but limited access and mostly uninterrupted
                        # by traffic signals.  In urban areas, intersections
                        # are with arterials and may use traffic signals.  In
                        # rural areas, intersections are with county roads or
                        # other highways.
                        highway = trunk

        else:
                # Here we define 'importance' as a relative and somewhat
                # subjective term that depends on a few things:
                #  * How busy is the road (cars per day)?
                #  * What is the speed limit?
                #  * How wide is the road?
                #  * How many lanes of traffic?
                # Compare the road to others in the area (or another
                # similarly-sized town) and decide its relative importance.
                if (importance == high):
                        # Busiest roads:  multi-lane and often lined with
                        # many businesses in urban areas; wide and high-speed
                        # (55+ MPH) through rural and unpopulated areas.
                        highway = primary
                elif (importance == average):
                        # Less important than a primary:  less traffic; fewer
                        # businesses and fewer lanes in urban areas; narrower
                        # but still high-speed (typically 55 MPH, 2 lanes)
                        # through rural areas.
                        highway = secondary
                elif (importance == low):
                        # Other arterial roads or somewhat important but
                        # less-traveled roads
                        highway = tertiary
                else:
                        # County roads, typically on a 1-mile grid
                        highway = unclassified

If the US had no signs this would be ok, but the US does have signs. --Nickvet419 07:00, 27 February 2009 (UTC)

"Signs" have nothing to do with this. What roads are *signed* as is the point of the ref tag, name tag, and relations. Look at any commercial road atlas and you'll find that (with the exception of toll roads) Interstate, US, and state highways get line colors and styles that correspond to the quality and connectivity of the roadway, not the shield shape. Look at European atlases and the same things occur (Michelin's maps of France have "N" roads in several different line styles). If you are going to justify a radical change in the practice for North America, you can't just appeal to "Users" you've talked to (none of whom are commenting on this proposal as far as I can tell) as a basis. Lordsutch 08:17, 27 February 2009 (UTC)

I took a look at the atlas as you suggest and I see that they mark all the state and US routes as principal roads which is a diferent catagory than other roads. They also have diferent renderings for types of roads, divided highways, miltilane, ect... There are tags for road properties, lane, smoothness, speed. If you want the OSM map to look more like an atlas, you should request that the map render these properties. As for the eourope OSM map they lable highway tags based on signs (A-road, B-road). --Nickvet419 08:43, 27 February 2009 (UTC)

Yes, because the SIGNS REFLECT THE QUALITY AND IMPORTANCE OF THE ROAD IN BRITAIN. The signs in the U.S. don't; they reflect WHAT NETWORK THE ROAD IS PART OF, which is often an arbitrary administrative decision. For example, north of Terre Haute, Indiana, which road would you take towards Chicago? If you picked the U.S.-signed road, you'd be wrong; the state highway is better. More to the point, there is an existing standard in OSM that applies in all countries. We need to follow that standard. That means we can't promote trunks above motorways, and we can't redefine "primary" as "roads that happen to be signed with US-shaped shields." We have ways to mark what signs are on the road (the ref tag and the route relation schema) already. Lordsutch 02:31, 7 March 2009 (UTC)

The signs in the US and the UK have nothing to do with the road properties itself but the administration level of who is responsible for maintaining it. You should use road quality when there is no administrative designation. Also, SR63 north of Terre Haute, Indiana could be considered as a trunk clasification which would be a higher classification than the primary US41.--Nickvet419 03:24, 7 March 2009 (UTC)

In the UK, all the classified roads (M, A, and B) are maintained by the same agency. In the U.S., the signs on the road don't necessarily reflect who maintains them, although most Interstate, US, and state highways are all maintained by state departments of transportation. And in admitting that SR 63 should be classified as more important than US 41, you've essentially conceded that the importance of the road is more useful to OSM users than what signs are on it (which can and should be indicated via other tagging). Lordsutch 04:22, 9 March 2009 (UTC)

What I am saying is the signs should be the primary source of tagging a road. If the road should happen to fall in a higher class, the road can be promoted as in SR 63. SR 63, should not fall to a lower class than secondary because just of road conditions. The lowest class of a State Route should be secondary. --Nickvet419 04:57, 9 March 2009 (UTC)

No, the source for tagging highway is the physical layout. It does not matter if it is maintained by state, interstate, county, private .... This has to be tagged in the ref, or other tags. Don't try to mix different concepts. This will fail because then you will need 10+ values to cover all corner cases. If you feel it's important add an operator tag or some other tag. --Apo42 29 March 2009

Administrative classification or maintainer per se doesn't matter. Navigation does. A state or US highway is a road you can follow, from city to city or state to state. Having a highway change color multiple times as it enters and leaves a town, and in particular change in such a way that no one looking at the map (or editing it) can tell the difference between it and dozens of other similarly built roads in an urban area is not helpful. It becomes difficult to impossible to tell where the highway one is trying to follow actually goes.

In particular, no practical renderer can render shield or route markers dense enough for a user to follow a state or US highway on its route through even the smallest of towns. Within town, such roads are typically physically indistinguishable. Virtually every US atlas makes such distinctions as a matter of course - typically rendering state and US highways much more prominently than any major street, even if the street has eight lanes and the state or US highway has two. The reason why is that for navigational purposes roads that go from city to city or state to state are far more important than streets that go for a mile or two, no matter how wide they are.

However it happened, generally speaking the U.S. data already has its data coded to make a distinction between US and state highways and "residential streets". That is a very useful distinction. If we were to switch to new tags, we need editors and the renderers to display those routes in a different color, because the road network is what is most important for navigation. For such purposes, whether a road has six lanes or two is virtually irrelevant. It is obvious that when a highway enters town the number of lanes is going to go up. Where you need to make a turn to stay on the state or US highway is not.

A much better idea would be to adopt a new set of tags to classify streets by something akin to number of lanes and leave primary/secondary/tertiary/residential to distinguish network classifications (in the US: US highways, state highways, county highways/major streets, and other streets). If in the UK those classifications overlap with road width/capacity that is extremely convenient. In the US, rendering and navigating primarily by number of lanes is borderline useless. Shield and route markers are not an adequate substitute. Butlerm 21:45, 6 April 2009 (UTC)

I don't necessarily agree that the road network is most important for navigation. Suppose you want to quickly get from point A to point B. Think in terms of a routing algorithm. The most important road will most likely get you there faster, so the routing algorithm shouldn't spend much effort investigating roads with similar length but of lesser importance. In your example of an 8-lane road next to a 2-lane road, the 8-lane road will almost always be more important and better suited for getting you to your destination faster than the 2-lane road, even if it only goes for a short distance. Tag it as such to bias the routing algorithm toward the more important road.

Imagine a U.S. highway following an old alignment through a residential area, while nearby another U.S. highway is the main drag through town. Should both be given the same importance? Probably not. Should both be displayed the same? That's a rendering issue, and it depends on what you're trying to show. If you want to show roads by importance, then set up your renderer to use the highway tag. If you want to show the routes associated with each shield, then use the route relations and color everything appropriately. If you want some combination, then tweak your renderer's configuration to show what you want. We have the lanes=* tag as well if you want to factor that in. The point is, all of the information (relative importance, number of lanes, route shields) is tagged separately so that you can render it however you wish.

As far as your route shield rendering concerns, I don't see this as a problem. If you're determined to stay on the marked route regardless of how important the road is (as compared to others nearby), then you need a map that highlights routes instead of importance. U.S. travel maps are drawn this way so that you can easily follow the route shields while driving and ignore everything else. Use the right map for the job.--Elyk 05:52, 7 April 2009 (UTC)

A more serious concern is the definition of "primary", "secondary", and "tertiary". In both the U.S. and the UK, these refer to functional classifications. A primary road does not turn into a secondary road just because it loses lanes. In general, roads do not change classifications in between cities at all. That is because it is the property of the whole road from one city to another that determines its functional classification.

If someone wants to render a standard road map that colors roads by functional classification, what are they supposed to do? If we manually convert all the existing U.S. data from the functional classifications imported from TIGER to some sort of lane based system, that will become impossible. i.e. We are talking about throwing away perfectly good data and good terminology and replacing it with the wrong terminology for something completely different.

We have a tag for classifying roads by number of lanes. It is called "lanes". Two, four, six, eight - readily identifiable from aerial photos. No need to corrupt existing data. The way nearly all the U.S. data is now, the highway tags do not convey any specific number of lanes, and are wholly unreliable for that purpose.

Currently, we promote roads to higher classes based on functional considerations. That matches the TIGER data. And yet we are told to ignore functional considerations most of the time and do it based on physical cross section instead, which means we really ought to go out and eliminate the functional classification of all U.S., state, and county highways and replace it with an underspecified quasi lane based system based on data that we can only gather through manual inspection. That is a consistency nightmare. Tag usage should be reliable and orthogonal, not a random and arbitrary mishmash of two different classification systems. Butlerm 03:23, 10 April 2009 (UTC)

You might want to consider Proposed_features/Highway_administrative_and_physical_descriptions --Hawke 14:05, 10 April 2009 (UTC)

I agree mostly with Butlerm's comments, with a concession: administrative designation has only a moderate correlation with functional class. The way I've been tagging, Primary roads connect large cities, and are the major cross-country and cross-state routes (in the absence of Trunks or Motorways). This includes nearly all US routes, and a few state routes. Secondary roads connect small and medium-sized cities (and the larger suburbs). This includes a varying percentage of state routes, depending on how liberally individual states assign their state routes. In Ohio, it would be nearly all of them. It also includes some county roads that sometimes appear on state-level maps as "good connecting roads". It might also include parts of US routes whose long-range function has been usurped by a nearby Interstate. Major urban roads that are significant for a long enough stretch to make them viable cross-city routes can also be tagged as secondary. Tertiary roads are the remaining "through routes". In the city, they are the arterials that move people from a neighborhood to another neighborhood, and to the more significant routes. In the country, they are the "shortcuts" between towns. They're almost always county (or possibly state secondary) highways. They usually go for several miles without motorists having to stop. In mile-gridded areas, they may occur once out of every three to six miles, or they might stand out by going against the grid. If the road follows one side of a creek, it might qualify for tertiary. Then there's residential roads, which are the low-speed fabric of the city and suburbs. A residential road is pretty much only good for getting to a destination (be it residential, industrial, or commercial) on the road itself or one connected to it. The residential road's counterpart in rural areas is the unclassified road. Unclassified roads usually allow travel up to 55 MPH, if the pavement is of sufficient quality, but not for very long distances between stops or turns. Like residential roads, they're not good for through traffic. Residential and unclassified roads are usually city streets, or county or township highways. I think this is a good medium between the two extreme ideologies of highway tagging. It's all about a road's usefulness and suitability for travelling some distance. To tag a road's physical characteristics of capacity and speed at a particular location, we have the lanes and maxspeed keys. A routing engine that attempts to find the fastest route in an urban environment can take those into consideration. To tag a road's governmental designation, we have the ref key and route relations. I support the idea of a new, auto-navigation specialized map render which does more with those, because OSM's main slippy map is not meant to be autocentric. But I believe the system I've described works well enough to approximate the goals of both viewpoints. Vid the Kid 19:42, 11 August 2009 (UTC)

There is something to be said regarding having classifications strictly match the road network. Many state roads with legitimate route numbers are unsigned or minimally signed, usually as they are short and the former alignments of another road (e.g. NJ 156 in White Horse and unsigned NJ 167), they only exist to connect two major roads (e.g. FL 4080, assigned to the connector between FL 408 and FL 417 east of Orlando), or they are stretches of an otherwise locally-maintained road maintained by the state or county as a grandfathered or truncated route (e.g. NJ 13 in Point Pleasant (the Lovelandtown Bridge), NJ 59 (a state route that never was formed beyond a road that was simply acquired from a city) or Monmouth CR 45 near Keyport, which crosses a creek). These roads, for obvious reasons, can't be rated at the same level as a state or county highway that carries more load just because they're defined the same way. CrystalWalrein 01:22, 30 August 2009 (UTC)

State Highway References

There is a live dispute about the interpretation of the following text:

"State highways should have ref tags having as their values:

[1] US: (optional; few editors have chosen to use this designation) [2] The two letter abbreviation for the state per the United States Postal Service's state abbreviation list. [3] A space. [4] The designation of the highway, be it numeric, alphabetic, or a combination."

Many states include the state abbreviation in the official short form highway designation. However, in California, Utah and many other states, the official short form designations of state highways (the ones that appear on official signs and in official documents) do not include the state abbreviation, but rather include a prefix such as "SR " or "SR-" (for State Route) instead.

As such I propose that the ref tag for state highways always be in the official short form designation assigned the state that operates the highway, e.g.

e.g. "[state code] [nnn]" in New York, Nebraska, North Carolina, Kentucky, etc. "SR nnn" in Arizona, California, Nevada, Virginia "SR-nnn" in Alabama, Utah and so on.

This is the convention documented and followed by Wikipedia for state highways, by the way.

One of the reasons why this is important, is if the official prefix is stripped off and replaced with the two letter state code, the numbering may be ambiguous. Some states have both state highways (two letter prefix) and "state roads" (SR prefix), in addition to county roads/routes typically with a CR prefix.

Comments? Butlerm 01:34, 17 June 2009 (UTC)

I'm the other principle in this dispute. I've been tagging state highways as "[state code]-[nnn]". e.g.: UT-126. I agree that there is some ambiguity in what is specified for state highways/routes. I think that this should be resolved and have proposed to go with the consensus that is developed, as long as there are five other people (besides the two principles). What do the rest of you think?

Please keep in mind the comment that I've recently made above (in the dashes section) about how "ref" tags are actually drawn in current renderers. However, don't feel obligated to make a decision that current renderers will do well, just keep it in mind. — Val42 05:31, 17 June 2009 (UTC)

I've been tagging state highways in Michigan with ref="M xx", since they are officially signed with M (not MI). It is my understanding that in the long run the ref tag will be phased out in favour of relations, so I figured I'd just tag what's on the signs so the renderers produce nice looking maps for now.--Abgandar 16:24, 11 August 2009 (UTC)

If you do that, then it will be ambiguous between states, and between the US and other countries. Bad idea (IMO of course). --Hawke 16:45, 11 August 2009 (UTC)

I support tagging the ref key with whatever is the regional style for abbreviating state routes. The value of the ref key currently comes out in two places, unformatted: on the maps, and in directions. In both cases, I think it's most practical for the formatting of the route designation to be concise and consistent with what's commonly done in that area. Ambiguity isn't really an issue, as most maps don't distinguish between different states' (or provinces') routes anyway. Besides, the average driver isn't likely to pay attention to the difference between an Ohio state route shield and a Kentucky shield, or even a US route shield. Finally, we have route relations to store the actual, specific designations in the data. When someone codes a renderer to use that data, they'll have to write some code to pull together the network and ref (and possibly modifier) values anyway, so they might as well write that code to display it in a practical way, possibly even using correct route shields. (This should be possible with just network and ref, without a symbol tag hyperlinking to an SVG graphic. It would require rules for each shield design, but I think this is reasonable if the renderer is intended primarily for road navigation.) Vid the Kid 19:57, 11 August 2009 (UTC)

Not everything is in a relation. Putting county routes in a relation would be a huge pain for very little gain. --Hawke 00:34, 12 August 2009 (UTC)

You could say the same about refs on county routes, since most of them are unsigned reference routes anyways. I think in the long run, relations on routes is better than constantly fussing with a freeform ref. There are currently some discussions on the dev mailing list about using "containing areas" in reverse geocoding (in Traveling Salesman, for instance), to replace the unhelpful is_in tag we have today. Those efforts will lend themselves nicely to disambiguating routes, so "M 1" in the UK won't be confused with "M 1" in Michigan. (Though I'm still not sure how there would be confusion and what application it would matter in.) – Minh Nguyễn (talk, contribs) 07:33, 12 August 2009 (UTC)

"unsigned reference routes"? Huh? Are you saying that there are not county route signs? I beg to differ. As for the issue of confusion, having only one ref=M nnn set would allow a renderer to more easily choose an appropriate symbol for each location, such as the US highway shield (or in this case, it doesn't need to figure out what country/state the road is in, in order to decide whether it should be the Michigan state highway symbol, the Missouri highway symbol, or a UK motorway. --Hawke 16:20, 12 August 2009 (UTC)

I doubt anyone is going to want to write code that tries to parse a ref tag to determine the correct symbol. Even if everyone agrees on and uses (yeah, right!) a uniform and unique ref tagging scheme, it would still be a fair amount of work to separate the network from the number, and the different routes from each other, all from one long ref string. It's much easier to get that information from route relations, which already have the information organized in an unambiguous way. (Note: the TIGER import didn't create ref tags. And the ref tags in use now aren't very consistent. For only slightly more work than it would take to assign or reformat ref tags for every state route, US route, and Interstate in the country, all the work on route relations for those networks can be completed.) In short, I've given up on using the ref tag for storing actual, precise, unambiguous route designation information, because it will never be used as such. Rather, I use the ref tag to store the most concise and reasonable description for the road's (most important if many) route designations. And regarding county routes, I don't even bother with a ref tag unless the county road number is signed with a blue pentagon or white square shield. If it's just tiny text below the name on the ordinary road name sign, it's too obscure for navigation purposes and the ref tag. If the county route number is the name of the road, displayed on an ordinary road name sign, then I put that (or, as the case usually is, leave it where TIGER put it) in the name tag. Vid the Kid 01:41, 13 August 2009 (UTC)

Yes, and in plenty of urban counties, county routes are either completely unsigned or the only signage is a C number on a reflector stick alongside the road (not sure what the technical term is). Obviously, some states like New Jersey, West Virginia, and Florida make much greater use of county route shields. Just like is_in these days, ref should be treated as a convenience, not an absolute necessity. (Boundary and route relations should be used instead, whenever the designations are that important.) – Minh Nguyễn (talk, contribs) 10:17, 13 August 2009 (UTC)

It appears that this thread is not moving towards any sort of consensus. If it helps, the actual road signs only show the route number in black on a white beehive.[8] However, the routes are officially designated (in full) "State Route <number>". Other states will vary. Shall we go with the signage or the official designation? — Val42 07:19, 16 September 2009 (UTC)

Neither, I think. Many route networks post just the number on signage, and that would be too ambiguous for ref to be useful. The full designation is long enough to be put in name if that's a good idea. In any case, I don't think we should be making a huge deal about ref, since relations would be a much more extensible and flexible way of tagging. ref seems like more of a shortcut to me, when all a map or router needs to do is display some quick-and-dirty info to the user. So I'd say just tag it with whatever would be most helpful to an OSM-toting road warrior deciding which exit to take (keeping in mind a U.S. Route and state route with the same number may be in close proximity). – Minh Nguyễn (talk, contribs) 08:20, 16 September 2009 (UTC)

Urban areas

Urban areas need multiple grades of roads to show the relative importance of the roads. Number or lanes and width isn't enough. I propose that we use trunk/primary/secondary/tertiary as indicators of importance within cities. --Muir

That's what's already done, and it's not any different between urban and rural areas in that regard. --Hawke 18:22, 1 September 2009 (UTC)

Talk-us unpaved discussion

I have been reading thru these posts and havn't seen a consensus/summary yet. In my view it should be reasonably straight forward based on the tags we have. The point is to describe what is actually there.

highway= is for the type of road regardless of condition. A paved surface is assumed unless otherwise stated. If it does not have a name (and thus no addresses), it should be a track. This would typically be a 1 lane (total) or possible wide enough for 2. This probably assumes an unpaved surface by default.

See also Tracktype= for further track classification. Key:tracktype

highway=path is non-motor vehicles. This is not to say it isn't possible to drive motor vehicles on it, just not designed for it or in common use. Basically only for servicing or emergences. This may have any surface or maintenance level.

Surface= is for describing the condition of the road when it does not match the assumed default. Unpaved works but isn't that descriptive. Gravel, dirt ect. would be a better choice.

Access= if it needs to be tagged private or other than full public access.

If there are further situations that need to be tagged, we probably want to either apply more tags to clarify the conditions, or better yet create a new subset of tags for specific use. I'm thinking of someone wanting to start tagging offroad trails for bikes, or 4wheel drive ect. I would think because of the narrowed focus of something like that it should be well separate from what most cars can drive. Sort of an oxymoron off-road roads.... :) Probably under Tracks though.

And as usual if other applications do not use the tags right, we need to e-mail the authors and ask for a change to fit the tags. I'm sure they prefer that to digging in the wiki to see if someone started using something new/different.

FHWA Highway Functional Classification System

It appears to me that the classification system used by the FHWA covers and includes what everyone is trying to get at, in terms of highway:type, but in a more concrete and defined manner. Please read the guidelines at http://www.fhwa.dot.gov/planning/fctoc.htm. Ksamples 08:48, 17 September 2009 (UTC)

I haven't read the whole document yet, but the figures in the introduction are quite useful. Specifically, note the figures [9] and [10]. What in those figures are labeled "arterials" or "arterial street", I would say in OSM should be secondary or primary, depending on the sizes of the cities they connect — that is, if they don't already qualify as trunk or motorway. What those figures label as "collectors" or "collector street" should in OSM be tertiary highways. The remaining roads in the figures ("locals" in the rural diagram) should, in OSM, be unclassified roads in rural areas; and residential roads in urban and suburban areas, and in isolated small towns and residential developments. That's my take. Note that, in many cases, these arterial roads are state and US routes, and the US route designations often occupy the roads between the larger cities. This is why I think the OSM highway classes in the US should look similar to, but not necessarily exactly like, what resulted from the TIGER import. Vid the Kid 00:26, 19 September 2009 (UTC)

First, sorry for such a long post. I've read through the guidelines and apparently it's a requirement by the FHWA that all states use this class system. Georgia has published their maps and I've begun to reclassify the roadways around Athens, GA with good results. What I have noticed is that the primary roads that are classed according to tiger tend to be pretty accurate, not so great with secondary, and trunk and tertiary don't exist. I'm sure not all states publish their highway classification data, so I think these guidelines will give everyone the concrete definitions that we are looking for in trying to determine what class a road falls into. Below are the road definitions pulled straight from the HFCS guidelines and I'll list what I think the OSM equivalents are in parenthesis.--Ksamples 20:04, 19 September 2009 (UTC)

(Ksamples' post is below.) The reason the primary roads are mostly correct is that U.S. routes were without exception tagged as primary by the importers, and FHWA has a uniform standard for the quality and size of roads along U.S. routes. (Never mind, they don't; see Wikipedia.) Each state, on the other hand, has its own standard for state routes. Some states have much broader state route networks, which is why Kentucky and Louisiana, for instance, appear much yellower than other states on the Osmarender map. (In Louisiana, some state routes can be nothing more than short residential roads.) On the other hand, someone on the U.S. mailing list mentioned that many of Vermont's state routes are unpaved. So if we go with a more functional classification system, these states will need a lot of fixing. – Minh Nguyễn (talk, contribs) 08:13, 20 September 2009 (UTC)

I've found a few state maps of the HFCS. I'll see if I can find maps for all of the states and move this over to a new wiki page and see if I can start a discussion on the mailing list also. Obviously I'm for the HFCS and hope that we can adopt the guidelines for the US.

--Ksamples 01:02, 21 September 2009 (UTC)

State pages for highway functional classification

• Arizona - http://tpd.az.gov/mpd/gis/fclass/fcmaps.asp
• California - http://www.dot.ca.gov/hq/tsip/hseb/crs_maps/
• Georgia - http://www.dot.state.ga.us/maps/Pages/HighwaySystem.aspx
• Idaho - http://itd.idaho.gov/planning/GIS/MapBook/2008MapBook/Section1Maps/Functional_Class2015.pdf
• Kansas - http://www.ksdot.org/burtransplan/maps/CountyFunClass.asp
• Michigan - http://mdotwas1.mdot.state.mi.us/public/maps_nfc/
• Minnesota - http://www.dot.state.mn.us/planning/program/functionalclass.html
• Nevada - http://www.nevadadot.com/reports_pubs/Class_maps/
• New Jersey - http://www.nj.gov/transportation/refdata/roadway/fcmaps.shtm
• New York - https://www.nysdot.gov/divisions/engineering/technical-services/highway-data-services/functional-class-maps
• Ohio - http://www.dot.state.oh.us/divisions/transsysdev/programmgt/functionalclass/pages/functionalclassificationmaps.aspx
• Oklahoma - http://www.okladot.state.ok.us/hqdiv/p-r-div/maps/funct-class/rfc.htm
• Texas - http://www.txdot.gov/apps/statewide_mapping/StatewidePlanningMap.html
• Vermont - http://www.aot.state.vt.us/Planning/Documents/HighResearch/Publications/RuralFunclStatewide_2008.pdf
• Virginia - http://www.virginiadot.org/projects/fxn_class/maps.asp
• Washington - http://www.wsdot.wa.gov/mapsdata/tdo/functionalclassmaps/default.htm

FUNCTIONAL SYSTEM CHARACTERISTICS

AREA DEFINITIONS

Urban and rural areas have fundamentally different characteristics as to density and types of land use, density of street and highway networks, nature of travel patterns, and the way in which all these elements are related in the definitions of highway function. Consequently, this manual provides for separate classification of urban and rural functional systems.

Experience has shown that extensions of rural arterial and collector routes provide an adequate arterial street network in places of less than 5,000 population. Hence urban classifications as discussed herein are considered in the context of places of 5,000 population or more.

Urban areas are defined in Federal-aid highway law (Section 101 of Title 23, U.S. Code) as follows:

"The term 'urban area' means an urbanized area or, in the case of an urbanized area encompassing more than one State, that part of the urbanized area in each such State, or an urban place as designated by the Bureau of the Census having a population of five thousand or more and not within any urbanized area, within boundaries to be fixed by responsible State and local officials in cooperation with each other, subject to approval by the Secretary. Such boundaries shall, as a minimum, encompass the entire urban place designated by the Bureau of the Census."

Small urban areas are those urban places, as designated by the Bureau of the Census having a population of five thousand (5,000) or more and not within any urbanized area.

Urbanized areas are designated as such by the Bureau of the Census (50,000+).

Rural areas comprise the areas outside the boundaries of small urban and urbanized areas, as defined above.

Rural roads consist of those facilities that are outside of small urban and urbanized areas, as previously defined. They are classified into four major systems: Principal arterials, minor arterial roads, major and minor collector roads, and local roads.

Rural principal arterial system (motorway and trunk)

The rural principal arterial system consists of a connected rural network of continuous routes having the following characteristics:

1. Serve corridor movements having trip length and travel density characteristics indicative of substantial statewide or interstate travel.
2. Serve all, or virtually all, urban areas of 50,000 and over population and a large majority of those with population of 25,000 and over.
3. Provide an integrated network without stub connections except where unusual geographic or traffic flow conditions dictate otherwise (e.g., international boundary connections and connections to coastal cities).

In the more densely populated States, this system of highway may not include all heavily traveled routes which are multi-lane facilities. It is likely, however, that in the majority of States the principal arterial system will include all existing rural freeways.

The principal arterial system is stratified into the following two subsystems:

Interstate System (motorway).--The Interstate System consists of all presently designated routes of the Interstate System.

Other principal arterials (trunk).--This system consists of all non Interstate principal arterials.

Rural minor arterial road system (Tag:highway=primary)

The rural minor arterial road system should, in conjunction with the principal arterial system, form a rural network having the following characteristics:

1. Link cities and larger towns (and other traffic generators, such as major resort areas, that are capable of attracting travel over similarly long distances) and form an integrated network providing interstate and intercounty service.
2. Be spaced at such intervals, consistent with population density, so that all developed areas of the State are within a reasonable distance of an arterial highway.
3. Provide (because of the two characteristics defined immediately above) service to corridors with trip lengths and travel density greater than those predominantly served by rural collector or local systems. Minor arterials therefore constitute routes whose design should be expected to provide for relatively high overall travel speeds, with minimum interference to-through movement.

Rural collector road system (Tag:highway=secondary and Tag:highway=tertiary)

The rural collector routes generally serve travel of primarily intracounty rather than statewide importance and constitute those routes on which (regardless of traffic volume) predominant travel distances are shorter than on arterial routes. Consequently, more moderate speeds may be typical, on the average.

In order to define more clearly the characteristics of rural collectors, this system should be subclassified according to the following criteria:

Major collector roads (Tag:highway=secondary).--These routes should:

1. Provide service to any county seat not on an arterial route, to the larger towns not directly served by the higher systems, and to other traffic generators of equivalent intracounty importance, such as consolidated schools, shipping points, county parks, important mining and agricultural areas, etc.
2. link these places with nearby larger towns or cities, or with routes of higher classification
3. serve the more important intracounty travel corridors.

Minor collector roads (Tag:highway=tertiary).--These routes should:

1. Be spaced at intervals, consistent with population density, to collect traffic from local roads and bring all developed areas within a reasonable distance of a collector road
2. provide service to the remaining smaller communities
3. link the locally important traffic generators with their rural hinterland.

Rural local road system (Tag:highway=unclassified)

The rural local road system should have the following characteristics:

1. Serve primarily to provide access to adjacent land
2. provide service to travel over relatively short distances as compared to collectors or other higher systems. Local roads will, of course, constitute the rural mileage not classified as part of the principal arterial, minor arterial, or collector systems.

Guidelines on extent of rural functional systems

This table contains guideline ranges of travel volume (VMT) and mileage of each of the four functional systems for rural areas. Systems developed for each area using the criteria herein will usually fall within the percentage ranges shown.

System	Range VMT	Miles (%)
Principal arterial system	30-55	2-4
Principal arterial plus minor arterial road system	45-75	6-12
Collector road system	20-35	20-25
Local road system	5-20	65-75

Functional Systems in Urbanized Areas

The four functional systems for urbanized areas are urban principal arterials, minor arterial streets, collector streets, and local streets. The differences in the nature and intensity of development between rural and urban areas cause these systems to have characteristics that are somewhat different from the correspondingly named rural systems.

Urban principal arterial system (motorway and Tag:highway=primary)

In every urban environment there exists a system of streets and highways which can be identified as unusually significant to the area in which it lies in terms of the nature and composition of travel it serves. In smaller urban areas (under 50,000) these facilities may be very limited in number and extent and their importance may be primarily derived from the service provided to travel passing through the area. In larger urban areas their importance also derives from service to rural oriented traffic, but equally or even more important, from service for major movements within these urbanized areas.

This system of streets and highways is the urban principal arterial system and should serve the major centers of activity of a metropolitan area, the highest traffic volume corridors, and the longest trip desires; and should carry a high proportion of the total urban area travel on a minimum of mileage. The system should be integrated, both internally and between major rural connections.

The principal arterial system should carry the major portion of trips entering and leaving the urban area, as well as the majority of through movements desiring to bypass the central city. In addition, significant intra-area travel, such as between central business districts and outlying residential areas between major inner city communities, or between major suburban centers should be served by this system. Frequently the principal arterial system will carry important intra-urban as well as intercity bus routes. Finally, this system in small urban and urbanized areas should provide continuity for all rural arterials which intercept the urban boundary.

Because of the nature of the travel served by the principal arterial system, almost all fully and partially controlled access facilities will be part of this functional system. However, this system is not restricted to controlled access routes. In order to preserve the identification of controlled access facilities, the principal arterial system is stratified as follows:

1. Interstate (motorway)
2. other freeways and expressways (motorway)
3. other principal arterials (with no control of access) (Tag:highway=primary)

The spacing of urban principal arterials will be closely related to the trip-end density characteristics of particular portions of the urban areas. while no firm spacing rule can be established which will apply in all, or even most circumstances, the spacing of principal arterials (in larger urban areas) may vary from less than one mile in the highly developed central business areas to five miles or more in the sparsely developed urban fringes.

For principal arterials, the concept of service to abutting land should be subordinate to the provision of travel service to major traffic movements. It should be noted that only facilities within the "other principal arterial" system are capable of providing any direct access to adjacent land, and such service should be purely incidental to the primary functional responsibility of this system.

Urban minor arterial street system (Tag:highway=secondary)

The minor arterial street system should interconnect with and augment the urban principal arterial system and provide service to trips of moderate length at a somewhat lower level of travel mobility than principal arterials. This system also distributes travel to geographic areas smaller than those identified with the higher system.

The minor arterial street system includes all arterials not classified as a principal and contains facilities that place more emphasis on land access than the higher system, and offer a lower level of traffic mobility. Such facilities may carry local bus routes and provide intra-community continuity, but ideally should not penetrate identifiable neighborhoods. This system should include urban connections to rural collector roads where such connections have not been classified as urban principal arterials.

The spacing of minor arterial streets may vary from 1/8 - 1/2 mile in the central business district to 2 - 3 miles in the suburban fringes, but should normally be not more than 1 mile in fully developed areas.

Urban collector street system (Tag:highway=tertiary)

The collector street system provides both land access service and traffic circulation within residential neighborhoods, commercial and industrial areas. It differs from the arterial system in that facilities on the collector system may penetrate residential neighborhoods, distributing trips from the arterials through the area to the ultimate destination. Conversely, the collector street also collects traffic from local streets in residential neighborhoods and channels it into the arterial system. In the central business district, and in other areas of like development and traffic density, the collector system may include the street grid which forms a logical entity for traffic circulation.

Urban local street system (Tag:highway=residential)

The local street system comprises all facilities not on one of the higher systems. It serves primarily to provide direct access to abutting land and access to the higher order systems. It offers the lowest level of mobility and usually contains no bus routes. Service to through, traffic movement usually is deliberately discouraged.

Extent of mileage and travel on urban systems

This table contains guideline ranges of travel volume (VMT) and mileage of each of the four functional systems for urbanized areas. Systems developed for each area using the criteria herein will usually fall within the percentage ranges shown.

System	Range VMT	Miles (%)
Principal arterial system	40-65	5-10
Principal arterial plus minor arterial street systems	65-80	15-25
Collector street system	5-10	5-10
Local street system	10-30	65-80

Discussion

So I'm sure that you'll notice that there would be no urban trunks, which I think is valid. My understanding is that a trunk is not an interstate highway or a completely controlled access highway and it's not a slower speed primary highway. My thinking is that this can really only occur in a rural setting, i.e. high speed and few at grade road crossings. Closer into an urban area a trunk will become a primary road with slower speeds, more traffic, and more at grade road crossings.--Ksamples 20:04, 19 September 2009 (UTC)

That's not quite right. Expressways ("high speed and few at grade road crossings") do exist in urban areas, but with a lesser frequency. Quoted from above: "And yes, such roads do exist in built-up areas. Examples include: the M-5 north of I-696 in Novi, Michgan; Texas Highway 99 south of the Westpark Tollway on the outskirts of Houston; US-1 (MLKJ Pkwy / 20th St Expwy) between I-95 and US-23 in Jacksonville, FL; Route 2 between I-95 and Route 27 near Concord, Massachusetts; US-60 between I-17 and Loop 101 in Phoenix, AZ; and the Alton Parkway through Irvine, CA. (Those six examples were found with a quick look at Google maps and aerial imagery of just 8 or 9 cities I looked in.)"

I still believe that trunk should be reserved for roads that do not grant direct access to adjacent properties, a condition sometimes called "access partially controlled" because at-grade intersections with other public roads is still allowed. Applying it to every road that connects medium to large cities might be overkill, but more importantly, we lose what I think is a valuable distinction. As far as primary and secondary, you've pasted a lot of text and I'm not quite sure what exactly you've proposed. What I have in mind is similar to this: US routes are mostly primary, state routes are mostly secondary, but there can be less-important US routes (like those paralleled closely by an Interstate) that would be secondary, and some state routes connecting larger cities that would be Primary. And the threshold between secondary and tertiary can be adjusted depending on individual states' density of state routes. In some states like Kentucky, state routes are so prominent that many of them would be better tertiary. But for Ohio the density of secondary-and-better would match pretty closely the density of state-and-better routes. For the tertiary level and below, I think you have the same concept in mind as I do. Vid the Kid 04:59, 21 September 2009 (UTC)

Here's what I'm proposing:

• we should class roads according to function over form and form over designation.
• form is indicative of function and/or designation, but not always.
• designation is indicative of form and/or function, but not always.
• how do we know what class a road is? (from best to worst)

1. we have statistical traffic data for the road network.
2. we have local knowledge or live in the local community and have an idea of traffic patterns and flow.
3. we can visually see the form of the road (eg aerial photography, in person).
   1. limited access highways - motorway
   2. trunk?
   3. divided highways - primary
   4. highway - secondary
   5. tertiary?
   6. county road - residential/unclassified
4. we class it according to it's designation.
   1. interstate (eg I-75) - motorway
   2. trunk?
   3. US highways (eg US 441) - primary
   4. State highways - secondary
   5. tertiary?
   6. county road - residential/unclassified

• every US state has classed their roadways into the HFCS using statistical traffic data and local knowledge.
• we should use the HFCS data and translate it to the OSM classification.
• where there is no HFCS data, use the HFCS as a guidline and translate it to the OSM classification.

The sticking point seems to be how to translate the HFCS to OSM classes. I do not agree that the six examples of "urban trunks" should be classed so. The Novi, MI example is visually indistinguishable from I-696 as it is limited access for a few miles and therefore probably performs the same function as a motorway for that short length. So what's the definition of a trunk road?

• From Wikipedia: A trunk road, trunk highway, or strategic road is a major road—usually connecting two or more cities, ports, airports, etc.—which is the recommended route for long-distance and freight traffic. Many trunk roads have segregated lanes in a dual carriageway, or are motorway standard.
• From Dictionary.com: trunk road - noun - a highway [syn: highroad]

• highroad – noun - Chiefly British. a main road; highway.
• highway - noun - 1. a main road, esp. one between towns or cities: the highway between Los Angeles and Seattle. 2. any public road or waterway. 3. any main or ordinary route, track, or course.

So basically all interstates (motorways) are trunks, all trunks are highways, all highways are primary roads. Then the question is where to draw the line between the three. I suggest we use the HFCS definitions and translations to OSM that I listed above.--Ksamples 00:07, 22 September 2009 (UTC)

The problem is the tags aren't necessarily meant to follow their dictionary definitions. The mappers who started mapping Brittain chose a particular administrative highway designation class, and slapped "highway=trunk" on it. That particular class of highway designations doesn't particularly translate to the US. It seems that most US mappers tend to agree that "highway=trunk" should be defined something like "almost a freeway", though the details vary considerably. You pointed out that the M-5 "performs the same function as a motorway". But if you look closely, it has at-grade intersections with other roads. Because of that, few mappers will agree that it should be tagged as "highway=motorway". It performs like a motorway, but it's not. We need a tag just for this. Currently, "highway=trunk" seems to fit best.

We're starting to touch on another issue here. Currently, the usage of "highway=motorway" is limited to roads with a very specific form, regardless of function. With the lower classes, especially "highway=secondary" and below, most prolific mappers classify based on function (or designation) with little regard to form. It seems that, when a road is divided, limited-access, high-speed, and/or grade separated, form tends to trump function when it comes to what kind of line to draw on a map. This is true on paper maps as well as OSM. I don't think it would be wise to reject this tendency. That said, maybe there needs to be a new "highway=*" tag to cover almost-motorways — I would personally suggest "highway=expressway" — and then "highway=trunk" can be put to use more in line with its British origins. But until such a proposal gains momentum, I'll strongly support keeping "highway=trunk" for expressways, as discussed much higher up on this talk page. Vid the Kid 07:53, 22 September 2009 (UTC)

Not much else I can add to my side of the argument. It would be nice to have a standard such as the HFCS, where if I'm mapping in your neck of the woods and need to know what class a road should be, I can look it up. Just take a look at the Ohio HFCS [11] and see what you think.--Ksamples 23:20, 22 September 2009 (UTC)

Okay, thanks for the link to the Ohio stuff. I've taken a look at the Madison County (rural) and Columbus Southwest (urban) maps and considered how I'd translate them to OSM:

• Freeway¹, regardless of functional class → Motorway
• Expressway¹, regardless of functional class → Trunk²
• 02 Rural Principal Arterial → Primary³
• 06 Rural Minor Arterial → Primary or Secondary³
• 07 Rural Major Collector → Secondary
• 08 Rural Minor Collector → Tertiary
• 09 Rural Local → Unclassified⁴
• 14 Urban Principal Arterial → Primary or Secondary³
• 16 Urban Minor Arterial → Tertiary⁵
• 17 Urban Collector → Tertiary
• 19 Urban Local → Residential

¹A freeway is a high-speed, divided, multilane roadway with complete control of access. Entering and exiting a freeway is allowed only at entrance and exit ramps. (There are a few rare exceptions, where a minor service road meets a freeway at-grade.) An expressway is a high-speed roadway with partial control of access. Entering and exiting an expressway can be allowed at exit and entrance ramps or at-grade intersections with other public roads, but not directly to and from adjacent private properties. (There may be isolated exceptions where a house or farm has direct access.) Expressways are usually divided, multilane facilities, but not always; what roadgeeks call a Super-Two is included in my definition of an Expressway for OSM purposes. (See Wikipedia:Freeway, Wikipedia:Expressway, MUTCD section 2A.01, and User:Vid the Kid/Expressway.)

²It is my very strong opinion that there must be a tag to distinguish Expressways from "Conventional Roads" and, to a lesser extent, from Freeways. If we create a new tag for this purpose, I'll support it; until then, I use Trunk.

³If Expressways get a new tag, then Rural Principal Arterials and some Urban Principal Arterials should probably be tagged Trunk. Rural Minor Arterials and most Urban Principal Arterials can then be tagged Primary.

⁴Rural Local streets that are purpose-built to serve outlying residential communities or business/industrial parks should be tagged Residential. Also, Rural Local roads that form easy through routes or connections between towns should probably be tagged Tertiary. I think such roads are underrepresented in the HFCS, at least in Madison County.

⁵The Urban Minor Arterial classification is applied a bit overbroadly, in my opinion. A few of these (particularly if part of a signed route) should be tagged Secondary.

General notes: The Highway Functional Classification System maps I've seen tend to feature an "instant upgrade" where a road enters an arbitrarily-defined urban area. I've attempted to compensate for this in my translation example. I don't believe it's useful cartography to feature a road more prominently just because it's in an urban environment. In any case, the highway network as tagged should form a coherent network. That is, in each case when looking at only Primary-and-better, Secondary-and-better, or Tertiary-and-better roads, there should be very few dead ends, isolated segments, or noticeable gaps. Achieving this will require occasional deviation from the HFCS and its "official" translation to OSM.

It is my opinion that there is no simple HFCS→OSM translation that would produce a quality map. Some judgement calls by the mapper are still required. But I think the guidelines I've just given are a good starting point.

--Vid the Kid 20:46, 23 September 2009 (UTC)

+1 I made a commont on [[12]] regarding how to think about the classification, but I agree with Vid the Kid, as it seems Ohio matches California pretty well, which bodes well for general applicability. Merely pretending "trunk" doesn't exist in the US seems silly. It also seems to me that much of the disagreement is from there being a substantial difference between urban and rural trunks. I don't think they have to be meet an identical set of criteria. Mk408 19:10, 28 November 2009 (UTC)

+1 for this proposal --Sven L 16:23, 4 March 2010 (UTC)

I endorse the original proposal that uses trunk as a functional designation for interregional routes (rural MUTCD "primary arterials"). The MUTCD classifications provide a decent guideline for non-arbitrarily distinguishing between trunk and primary routes in rural areas that seems to be consistent with the planetwide/UK tagging conventions used in the design of tools and renderers. My only concern is if it isn't adequately consistent between states or areas, but it is almost certainly much more so than a classification based on official designation (US/state/county). Functional use of trunk is important -- many rural areas, particularly in the Western states (and Canada, if we want to be consistent with our neighbor to the north) have large areas only served by non-motorway, often two-lane major arterial routes. US 101, US 95, US 395, and US 50, for example, should be rendered at all levels on maps of California and Nevada, even though many sections are only two lanes. It's not helpful to have a map or routing tool refuse to display or route reasonably simply because no freeway or expressway is available. Speight 01:45, 19 December 2009 (UTC)

Trunk = surface expressway?

(TLDR for the above.)

When I first read this, I only skimmed it and thought I saw that trunk was being used for (MUTCD-definition) surface expressways - roads that are below freeway standard but above the typical standards of a surface road. This is how it seems to be used in New Jersey (except that some rural two-lane roads are also marked as trunk), and how I've been applying it in New York City (West Side Highway and some major boulevards and surface parkways as trunk). I think this makes a lot more sense than having it depend on a somewhat more subjective distinction of whether it's "enough of a freeway to be a freeway" (paraphrased). Speed limit under 50, for instance, would exclude a number of urban Interstates!

It's also worth pointing out that motorway and trunk are design criteria (how is the road designed?), while the lower classes are functional criteria (how is the road used?). --NE2 00:18, 19 December 2009 (UTC)

• As far as New Jersey, that's my fault. I usually assign trunk roads in the absence of high-quality roads within local proximity or if the road is a US highway or was part of one prior to 1968 (which is why I fought over the classification of PA 611, which was US 611 until 1968), and also to account for New Jersey's large county road system. I also extended the designation to improved portions of a trunk road even if there was no commercial zoning along it, unless the route itself (such as NJ 55 and NJ 90) or a new extension of it (in the cases of NJ 3 and NJ 18) exists only to be a motorway. (I was against having US 1, US 202, US 422, US 22, PA 309, and NJ 208 upgraded to highway=motorway mainly since there were already Interstate highways or dedicated freeways in the area or they just served as a bypass of a small town, but I eventually upgraded NJ 33 and NJ 15 to match.) That out of the way, I agree with you. CrystalWalrein 18:10, 19 December 2009 (UTC)

Well, US 1 etc. are motorways by definition. We're not tagging roads to try to force people to use Interstates. --NE2 20:36, 19 December 2009 (UTC)

Hoping to reduce inconsistencies

I'm hoping to be able to improve this and other pages to remove any inconsistencies. I guess this means first finding them, then probably some sort of vote on whether to go one way, another way, or allow either at the whim of the individual mapper. Would anyone be interested in helping? Or will I get silence, end up changing the pages myself, and get reverted? :) --NE2 06:25, 2 February 2010 (UTC)

As a small first step, does anyone object to me changing the motorway and trunk definitions to a general description of current practice? --NE2 07:26, 21 February 2010 (UTC)

What would that be? The motorway and trunk are defined on their respective pages. What do you want to change? Nakor 14:21, 21 February 2010 (UTC)

As it says here: Many people use trunk to mean "expressway"-grade arterials with at-grade intersections, major non-motorway intercity highways, or both. Your latter link says it's any divided highway, which is certainly not true. --NE2 18:03, 21 February 2010 (UTC)

Then is you do not agree with the definition of trunk I would bring it to the tags talk list. As you might have seen you will not get much feedback here as the OSM community communicates a lot more with the mailing lists. Nakor 13:14, 22 February 2010 (UTC)

Nobody agrees with that definition, since it's not being used anywhere. --NE2 20:36, 22 February 2010 (UTC)

So, what are your thoughts on the section above, proposing road tagging be roughly based on the functional highway classification schemes? In looking at it for my state, it makes a lot of sense.

• it's a fairly stable system to use which can be mapped to OSM tags,
• it's based on knowledge from experts in the field who know the roads
• it can be used for remote mapping (if you don't know the road yourself, you can look it up and have some idea)
• it has some consistency across jurisdictional boundaries
• it would alleviate much of the confusion/arguing --Neuhausr 19:29, 2 March 2010 (UTC)

Do you have any examples of areas tagged with functional classification? My guess is that it's probably a good start for someone with local knowledge to then improve on. --NE2 20:49, 2 March 2010 (UTC)

For Minnesota, the state DOT has a page devoted to it [[13]], with maps of counties and cities. It seems other states have similar portals (see a few above), and users could compare with OSM. Is this what you mean? --Neuhausr 22:43, 2 March 2010 (UTC)

I mean an example on OSM. Also, I would doubt that every state has such information available, and I would guess that there are some inconsistencies. I'll take a look at Florida to see how well functional classification would work there. --NE2 23:24, 2 March 2010 (UTC)

It's not a new tagging system, just a way to apply the current tagging scheme in a way that seems to have some advantages, so there isn't an "example". Given some time, I might work on an area in MN, but I did visually compare some areas with what is currently in OSM and it's pretty similar, and most of the potential changes from the state maps would probably be improvements more in line with how the roads are used. With a bit of Googling, I found some more states' maps--see links above--but not much luck with Florida. As for inconsistencies, well, there are always going to be exceptions/mistakes/disagreements, so if that's the bar, we may as well give up! :) --Neuhausr 04:10, 3 March 2010 (UTC)

Why functional classification won't work

I just mapped out the arterials (other than motorways) in Orange County (Orlando), and found the HFCS to be horribly unpolished, with gaps and outdated information. Don't trust me; check it out yourself by opening http://osmxapi.hypercube.telascience.org/api/0.6/*%5bHFCS=*%5d in JOSM and searching for HFCS="4 PAO" so that principal arterials are highlighted. Among the issues:

• The northbound principal arterial downtown is still on Magnolia Avenue, which became a minor street over 10 years ago; Rosalind Avenue (minor arterial) now handles through traffic.
• A couple pieces of the path SR 15 takes east of downtown are collectors. So is South Street, which is the westbound counterpart to the minor arterial Anderson Street.
• Several years ago, Winter Garden (west of Orlando) built the four-lane Daniels Road to replace the two-lane Vineland Road. The latter, while it still carries County Road 535, is no longer the main road, with a new mini-roundabout and a truck ban. Daniels Road is not even in the system.

It coulda been a contender, but it has too many problems to use. --NE2 05:32, 3 March 2010 (UTC)

I guess, as I said above, I'm just looking for something that'll solve 90-95% of the issue and give some guidance and uniformity. Based on that start, road tags can be applied with intelligence and updated local knowledge by OSMers. If you're really looking for *the* perfect system, it seems like a fool's errand. I'd be happy to be proved wrong, though! --Neuhausr 14:53, 3 March 2010 (UTC)

Except that this doesn't even seem to do that; there are a lot of collectors that should be arterials just for connectedness, and the distinction between principal and other arterial is also fuzzy (look at John Young Parkway in what I tagged). Now the general definitions of the classes might be a good starting point, but I don't see the actual classifications as being more than a starting point (and we already have a starting point: the TIGER CFCC codes). --NE2 15:43, 4 March 2010 (UTC)

I guess my point is that this whole issue is fuzzy. If it weren't, consensus would've been reached long ago. And to my mind, HFCS addresses that fuzziness and tries to make sense of it. I don't use JOSM, so your link above isn't helpful to me. But I did look at John Young Parkway, and I don't really understand your issue. It's classed as a Other Principal Arterial Urban in the Florida HFCS. According to the proposed mapping of classes to tags above, that would translate into primary in OSM, which is what it is in OSM. Are you saying primary is the wrong tag? I'm not personally familiar with it, but from imagery, primary seems reasonable.

The issues you initially mentioned above just seemed to be because Florida's data is out of date? This could certainly be an obstacle, and the lack of easy-to-find maps/data for some states could also be an issue, but I don't get the sense these are your root objections.

Do you have another idea in mind? What does "mirror the general characteristics of the UK's system" mean? I guess I can take this question down below.  :) --Neuhausr 16:54, 4 March 2010 (UTC)

I suggest you download JOSM; it's nice for doing certain types of editing, and for viewing this. I used FDOT's spreadsheet, which included Lake Nona Boulevard, built a few years ago. In particular, John Young is urban minor arterial from Church Street (just south of SR 408) to US 441, but urban principal arterial-other south of Church Street. (Church Street, by the way, is where maintenance changes from county to state.) Lee Road, John Young's continuation beyond US 441, is also principal-other. That's not as bad of a problem as some of the other issues, though, especially with respect to connectivity. I found some maps; they're from 2000, but seem to match in all the important places. Orange County is on page 3. --NE2 18:29, 4 March 2010 (UTC)

Proposed first principles

We're never going to get anywhere if we don't agree on the general idea of what we're trying to do. So I'd like to propose the following as a first draft of what we want to strive for:

1. In the UK, where OSM began, classes from motorway down to secondary are explicitly defined by the government. The U.S. has no such system, but we should try to mirror the general characteristics of the UK's system in the absence of a good reason to do otherwise.
2. Ref tags, which keep track of the route numbers on a highway, should be human- and machine-readable.

I'm personally open to almost anything that follows these principles (though not quite as open as I was when I joined; one tends to get used to a certain way of doing things). Does anyone object to these principles? --NE2 01:53, 2 March 2010 (UTC)

Sorry to butt in, but while the highway tag values are originally patterned after the UK road system, it's no longer true anymore (I think they are tagging primary A-roads as "trunk" and non-primary A-roads as "primary" in OSM). --seav 05:32, 2 March 2010 (UTC)

Ah, my mistake (for those reading along, trunk roads are maintained by the national government, while primary A-roads are a slightly different system that was presumably created for political reasons; primary A-roads have green signs). There's still a strict equivalence though, based on the class of route and color of sign, which doesn't work in the US for several reasons. --NE2 05:45, 2 March 2010 (UTC)

On ref tags: there is no syntax that is both human-readable and machine-readable in all cases. But I have a compromise solution to propose. Ref tags on ways should be concise and human-friendly. That is, it should represent how a typical local human would describe what route(s) the particular section of road is a part of. This may be only a subset of the full list of routes utilizing that section of road. This description, while approximate and possibly ambiguous, is sufficient for drawing a static map or writing directions for human drivers. On the flipside, purists and roadgeeks would like to store a complete, unambiguous, machine-readable description of every route in the data. This information can't adequately be addressed by ref tags on ways, especially where many routes overlap, and trying to do so would inconvenience most users of the data. Luckily, we have these route relations that are perfect for defining a complete route, independently of other routes. The network and ref tags of a route relation together form an unambiguous and machine-readable (also generally human-readable if not immediately driver-friendly) description of what the route is, and the members of course define where it goes. Any user of the data who actually cares about the particulars of all routes using a road (for example, a renderer designed for roadgeeks) can go to the trouble of parsing the route relations; but most users only need a single, simple and concise label for any piece of road, and the ref tag on the way is perfect for that. Vid the Kid 11:32, 2 March 2010 (UTC)

We're not dealing with specifics right now; these are general principles. What I mean by "human readable" is that a human can take the ref tag and understand exactly what it says, even if it's not the most concise way of saying it. Most tags I've seen satisfy that. (But we shouldn't omit routes because we think people don't care about them; that's tagging incorrectly (in other words, New Mexico-style).) --NE2 12:08, 2 March 2010 (UTC)

I have no objection to the statement that ref tags should be both human and machine readable; I don't know in which cases a machine must read the ref tags; as noted above, renderers should use the relations instead of ref tags. MikeN 17:17, 2 March 2010 (UTC)

I have a problem with ref tags on ways and relations following different semantics. Firstly, because it is confusing and secondly, because they are redundant. There is no reason to have ref tags on both ways and relations other than the fact that ref tags on relations are not widely supported, yet (at least not by the main renderers). Once they are supported the ref tags on the ways should be dropped.

IMO, ref tags should foremost be machine-readable by machines that are not aware of any particular highway system. That means that it should be possible for any machine to present the contents of ref tags literally to the user and the user should be able to make sense of it. While it is quite easy for an application that knows about the US highway system to extract the route number from ref="BUS US 23" it is much harder for an unaware application to make sense of network="US:US:BUSINESS", ref="23".--Mjulius 18:32, 2 March 2010 (UTC)

Oh, and as an aside, there's a simple way to render long ref tags: drop everything after the first (or second, or whatever) semicolon. A really smart renderer can show each route in a separate shield. --NE2 20:52, 2 March 2010 (UTC)

I can see that this has already devolved into a war of words over whether "ref" or relations should be used. Nothing has been said about your first point. I've subdivided this section into the two subjects that you've outlined above. I wish you luck because I didn't get anything done when I tried to get something smaller resolved. — Val42 05:16, 3 March 2010 (UTC)

I just found an example of one that's not unambiguously readable by human or machine: "US 1/9 Truck". Does this mean US 1 and US 9 Truck? Or US 1 Truck and US 9 Truck? Or US 1 and 9 Truck? Or US 1 Truck and 9 Truck? No matter what rules we set up, shortening the ref like this will create ambiguity in certain cases. --NE2 14:20, 4 March 2010 (UTC)

Ref tags on ways should be simple, concise, user-friendly. (Yes, "US 1/9 Truck" may seem ambiguous, but that probably matches pretty well what's on the ground.) Route relations are perfectly structured for unambiguity and machine-readability, so let them handle that task. This way, we can accomplish both machine-readability and human-friendliness. Who says the two features have to apply to the same mechanism? The way I see it, it's not redundancy, but comprehensiveness. My full opinion statement here: User:Vid the Kid/On ref formats Vid the Kid 15:14, 4 March 2010 (UTC)

Well, reassurance would be, top to bottom, TRUCK/US 1/US 9. If it were US 1 and US 9 Truck, it would say US 1/TRUCK/US 9. --NE2 15:39, 4 March 2010 (UTC)

Ugh, my fault. I should have just gone with ref=US 1 TRUCK; US 9 TRUCK doing that whole thing, but as you're used to signs along the corridor that say '1/9', '1-9', and '1&9', you wonder why they didn't just cut US 9 off at the ankles (or better yet, assign a new route number like they did in the case of NJ 166 in Toms River).... CrystalWalrein 03:11, 5 March 2010 (UTC)

No problem; I'm just throwing it out there as an example of what I mean. You're safe for now, but if we get lost you'll be the first to be eaten. --NE2 03:23, 5 March 2010 (UTC)

Highway classes

Copied from section above:

• In the UK, where OSM began, classes from motorway down to secondary are explicitly defined by the government. The U.S. has no such system, but we should try to mirror the general characteristics of the UK's system in the absence of a good reason to do otherwise.

I think the HFCS discussion and my guidelines for translating that to OSM highway classes (above, on this page) is a good way to go. It's not an exact specification — there's room for judgement calls on the part of (preferrably local) mappers — but it's better than the rather subjective and sometimes contradictory guidelines we have now, which can be wildly misinterpreted. Also, for a while now I've been simmering a way to finally separate form from function, bring US tagging a little closer to British/European practices, and preserve some uniquely US road distinctions, all while maintaining almost complete backwards-compatibility with existing applications of the data. I'll have to write that up into a proper proposal soon (especially now that I've hyped it up so much). Vid the Kid 15:14, 4 March 2010 (UTC)

See above: #Why functional classification won't work. Also, you're getting into specifics; do you disagree with the general principle? (By the way, separating form from function would be great in the UK too, where you have motorway-standard roads that are trunk because they don't want to ban certain vehicles.) --NE2 15:39, 4 March 2010 (UTC)

Can you expand on "mirror the general characteristics of the UK's system"? What are you getting at? --Neuhausr 16:56, 4 March 2010 (UTC)

Just a general statement that trunks should connect major cities, secondaries should be used by relatively local traffic, etc. --NE2 18:16, 4 March 2010 (UTC)

At the risk of beating a dead horse, did you read the info above at #FUNCTIONAL_SYSTEM_CHARACTERISTICS? Because what you describe seems just like the sort of thing described in the HFSC. (whack! whack! OK, that's enough I guess) --Neuhausr 22:38, 4 March 2010 (UTC)

Quack! Quack! Maybe it walks, quacks, and looks like a duck, but it has two beaks :) --NE2 02:32, 5 March 2010 (UTC)

Route tagging

Copied from section above:

• Ref tags, which keep track of the route numbers on a highway, should be human- and machine-readable.

Must these two qualities apply to the same string? My full opinion statement here: User:Vid the Kid/On ref formats Vid the Kid 15:14, 4 March 2010 (UTC)

No, but if there's a separate human-readable string it should be just as unambiguous. --NE2 15:45, 4 March 2010 (UTC)

Adoption?

If I'm not mistaken, there's no objection to the first principle, only argument about how best to apply it. As for the second, the only objection is with how to store the designations. Do the following sound good?

1. In the UK, where OSM began, classes from motorway down to secondary correspond to types of highway explicitly defined by the government. The U.S. has no such system, but we should try to mirror the general characteristics of the UK's system in the absence of a good reason to do otherwise.
2. It should be reasonably simple for a human and for a machine to determine the route number(s) assigned to a given way, using the ref tags of the way or its containing relations.

--NE2 05:59, 6 March 2010 (UTC)

Hopefully silence equals consent :) I've created a sort of FAQ at User:NE2/classification FAQ; I'd appreciate some comments on it. --NE2 18:09, 9 March 2010 (UTC)

I have to vote for classifying by physical characteristics. I'm thinking in terms of end users. My 75 year old father looks at a map and wants to get from point A to point B. He is going to look at the shortest route, but that might be minor roads with lots of cross traffic and traffic controls that might be slow. So he will also look for a major route that would have a faster travel time and still get him as close to his destination as possible before exiting to minor roads. He will know this by the way the road is drawn and colored on the map. And that is what it all comes down to, how will users actually use the maps.

The people advocating the use of administration classification draw out Interstates, toll roads, and US Highways until State Highways are classified as secondary. I just don't think that this is consistent with the OSM highway tag descriptions and leaves too little room (too few tags) for other roads. Besides, there are ALWAYS exceptions (based on physical characteristics) that could cause the roads to be classified higher. So...

I don't think that there is any argument that federal interstates should be classified as motorway. That is where the consensus ends. I will reference the OSM highway tag descriptions, which are British based, but I don't really care about the British road system and their classifications. This is about U.S. roads and in the U.S., "Main St." in Anytown USA should be listed as primary. This is where we start, "Main St." USA. Main St. usually leads out of town to another town. It may be part of a State Highway or US Highway and by the OSM standards, seems to me to be primary. It may drop or rise in classification when it leaves or enters the town, but that change in classification (ie. color of road on the map) gives the casual user of OSM maps a easy visual reference to the type of road to expect in that location. Isn't that what we want?

So we have motorway and primary defined. So by extrapolation, anything built to motorway standards is a motorway. Administrative classification doesn't matter, if it is limited access with no at-grade intersections, it is a motorway. Anything between motorway and primary is trunk. That fits with OSM physical characteristics of trunk as being one step down from motorway. A trunk road would be a divided highway with some at-grade crossings but with cross traffic yielding to the trunk road traffic.

Since Federal Interstates, toll roads (use highway=motorway, toll=yes) and some/most US Highways are typically built to motorway and trunk standards and are defined, then, ignoring the motorway and trunk roads, what would be the primary route between cities? This seems to conform to OSM descriptions of primary. This leaves plenty of room for the use of secondary, tertiary, and residential tags within towns and major urban areas.

Don't get me started on the unclassified tag...

As for name and ref tags, isn't the contents of the name tag usually rendered spelled out on the road and the contents of the ref tag usually rendered as a "shield"? If so, then yes, they should be both human and machine readable. "I45" rendered in a shield tells me that is Interstate 45, "US90" is US Highway 90, "TX6" is Texas State Highway 6. A highway with multiple designations should be something like "US290:TX6" with the higher classification listed first. Seems simple, am I missing the argument? Maybe we can convince the people working on the rendering engines to render a separate "shield" for each item that is separated by a colon (:) in the ref tag and display the shields side by side, like you see when you are actually driving the road.

From above, I like the "separate theory, Texas style", "organized tagging breakdown" (mine), and the "decision tree". I think that the main United States roads tagging page needs to be rewritten in a more organized form, maybe similar to the "organized tagging breakdown" above, so that it will be easier to read for first time users. This discussion has been going on for a couple of years, it's time to stop beating this dead horse and come to a consensus. You've got my two cents. --Xsintrik 04:54, 10 March 2010 (UTC)

I don't know if you're actually talking about physical characteristics here. In large cities, Main Street (or whatever they call it) does not have higher characteristics than other nearby streets. So downtowns would be a sea of primaries. --NE2 09:44, 10 March 2010 (UTC)

In addition, Main Street is not always a main highway; in Buffalo, New York, it's a pedestrian street with light rail down the middle. --NE2 12:59, 10 March 2010 (UTC)

Any system that we come up with will have a certain amount of subjectivity to it. If "Main St." in your town doesn't warrant a primary classification, change it. Even if "Main St." has the same physical characteristics of "2nd St.", if "Main St." is used more (higher traffic - links to higher classification roads), then it should be categorized higher. I agree with the point that you made on Dec. 19th, 2009 when you said "It's also worth pointing out that motorway and trunk are design criteria (how is the road designed?), while the lower classes are functional criteria (how is the road used?). There is no perfect, non-subjective system, but a little combination of form and function ought to do the trick. So can I assume that other than "Main St.", we agree on everything else? :) --Xsintrik 19:02, 10 March 2010 (UTC)

I agree with what you just wrote. I don't remember everything you wrote above, but we both seem to believe that we shouldn't classify solely by physical characteristics. Physical characteristics (below motorway or trunk) will mainly be an indication of what the main roads are functionally; for instance, in many areas, a centerline might almost always imply at least tertiary. In the FAQ, what I'm replying to is the suggestion that sometimes comes up to only use qualitative physical characteristics (width, smoothness, speed limit) and not use the classifications at all. I know, it sounds like a strawman, but it's been suggested :) --NE2 19:43, 10 March 2010 (UTC)

It seems that there are no objections to the FAQ? Or have people decided this is a waste of time? --NE2 17:40, 13 March 2010 (UTC)

Just a simple question about motorways

Has it been established that non-Interstate freeways are motorways? That's what all the guidance on the wiki says, and what common practice is around the US, but I'm currently arguing with someone who downgraded non-Interstate freeways in the DC area to trunk or primaty, and is citing discussions from 3 years ago to show the lack of consensus. --NE2 15:01, 11 March 2010 (UTC)

I have limited liking for the idea myself. I can agree with designating a named limited-access parkway (such as the Garden State Parkway or Florida's Turnpike), a route that is completely limited-access (such as PA 33, NJ 55, FL 528, or Arizona's Loop 202), or a part of a route that did not exist as part of the original, or deviates wildly from the original alignment, but is completely limited-access (such as DE 1, NJ 42, NJ 18, or RI 4), or any limited-access toll road as a motorway, but a mere by-pass of a few small towns isn't quite a motorway to me. I can see your point, but.... CrystalWalrein 01:37, 12 March 2010 (UTC)

Well, here it includes SR 27 (Washington Boulevard, a freeway bypass of the Arlington Cemetery) and the George Washington Parkway (freeway north of SR 27, except for one access point into Turkey Run Park near the north end). See here. --NE2 11:14, 12 March 2010 (UTC)

National Highway System and usage of Trunk classification in the US

One parameter that could be useful in determining trunk status is whether or not the road is included in the National Highway System. The NHS replaced the old Federal Aid Primary and Secondary road classifcations. Interstates are in the NHS by default nationwide, as are most non-Interstate motorways and major highways that are not in close proximity to an Interstate. The route can be US, state, or even an unnumbered city street, if the corridor they serve are deemed of sufficient importance. An NHS route doesn't even have to be dual carriageway, but only serve as the primary route in its corridor, thus likely to be handling above average or even Interstate-level traffic loads.

It seems the closest way to adapt the rigid British classification system and its colors (where the M-A-B(T) classifications decide it) to the less rigid US road hierarchy (I-US-State can all be a motorway; the only firm rule is that Interstates must be one), and show the relationships between the Interstates and these major routes. In my experience, a lot of the routes where it's a toss-up between motorway-trunk (my local example would be MD 90), are in the NHS. --Mdroads 3:30, 22 July 2010 (UTC)

Setting aside the possibility of pork or a bias towards military base connections, I don't think it's suitable as more than another data point to take into account. For example, in New Jersey, US 22 (parallel to I-78) is on the NHS east of US 202-206, but not west, despite being about as major and built to the same standards. Perhaps this is a holdover from the late completion of I-78 east of I-287, or perhaps it's because the eastern part is more urban, but I can't see the classification changing in Somerville. And look to the northeast - that's a lot of NHS routes, some serving the same corridors as others. I recommend using a tag like NHS=* (which I've tagged in Florida and New Jersey) so anyone who wants to render NHS routes can do so, and the data is there if we do decide to use it. --NE2 06:57, 22 July 2010 (UTC)

Is Trunk really necessary in the US?

I personally see trunk roads not necessarily high-speed, or even divided, but often as high-traffic, many being overloaded (and having safety concerns), often in places where an Interstate/motorway is impossible for whatever reason. When they reach cities/towns, they can go through them on surface streets if unbypassed. Again, I'm looking at the British model for how the map looks, and the relation of motorways to trunks. The prevailing opinion on tagging US trunk roads is to keep to physical characteristics, a trunk road essentially being a 'near-motorway' mostly with interchanges and some type of controlled access. There's only one problem with the latter; although we're not supposed to tag for the renderer, the resulting map basically looks garish, with green transitioning to red and back on the same route.

But since the only consensus on trunk in the US is that there is none, why not depreciate highway=trunk as the basis for a render color in the US? If using NHS status as the basis, they can be anything physically. Some aren't even divided, and some are city streets. If a user does wish to render those roads differently, they can use NHS=* tags on ways/relations to render those as they see fit. The problem comes in when an NHS route hits a town, and is no longer high speed and/or divided. Say, US 222 in Lancaster, PA. When it reaches the southern limits of town, it splits into two one-way streets, then a single street, before reaching the motorway bypass north of town. However, it is still the best route through town, and receives enhanced funding. Many others want to stick to physical characteristics (also valid), and thus must revert at least down to primary upon reaching town.

I like what NE2 has done with the NHS=* key; NHS should be tagged as a separate item. Most would have to be tagged at the way level, since NHS corridors can switch routes even in the same corridor. Interstates (in by default) could be tagged at relation level. I would say that there are varying corridors in NHS... mainline, STRAHNET (Strategic Highway Network) corridors, and intermodal connectors. Some of the intermodal connectors are short and not as important as the first two; different tags under the NHS key can help there. It can also help in deciding, as trunk does now, what primary roads to show at lower zoom levels. We cannot know exactly how the data will be used, and what things the users will deem appropriate. Everyone can have their cake and eat it too. --Mdroads 07:22, 22 November 2010 (UTC)

Yes, trunk is necessary. Too few classifications makes for limited usefulness in telling which highways are the most major (I've seen this where I was using tertiary for both two-lane collector streets and four-lane inter-suburb routes, and solved it by bumping the latter up to secondary). I see physical characteristics as a proxy for importance - for example a long-distance rural four lane road is most likely at least primary, and often trunk (if not bypassed by a better road). A road with controlled access is going to be major no matter what, and it seems reasonable to use trunk for it too, though I would not be opposed to using a different tag such as adjacent_property_access=* if we can get information as to where access truly is controlled without looking through individual right-of-way plans. (By the way, NHS is just as biased and unpolished as any other classification - STRAHNET for instance includes more routes near major military bases, such as in southern Georgia.) --NE2 10:05, 22 November 2010 (UTC)

Better Guidelines for roadway classification

Roadway classification in the United States is subjective, there is no getting around that fact. No amount of discussion is going to fix that. Guidelines which only focus on each road separably without considering the entire network will lead to inconsistent results. I have created a better set of guidelines at United States Roadway Classification Guidelines. Please look it over and give feedback on the page discussion tab (not here). Kevina 21:58, 26 July 2010 (UTC)

Content from 'Highways' article

I have moved this US specific information from the Highways article here. Is there anything new in this? if so fee free to integrate it into this article. Thanks.

Content cut from Highways

Interstate highways should always be tagged with highway=motorway.

US Highways should be tagged with highway=primary. State Highways and County Highways should be tagged with highway=secondary. Any of these which is a divided highway with high speeds (65mph+) and intersections with other roads, and legal for bicycles and motorbikes to use, should be tagged with highway=trunk.

Sometimes a tertiary road will be physically larger than a primary or secondary road. This is acceptable.

Alleys should be tagged as highway=service

In OSM language the Highway feature is used to designate what we call roads.

A motorway is a four+ lane, limited access, grade separated freeway. These can include Interstates, US Highways, State Highways, County Highways or even Farm to Market Roads if they meet certain criteria. These criteria are limited access,the use entrance/exit ramps to access the freeway. Intersections with other roads are at grade separated crossings or ramps. A grade separated crossing means one road goes over or under the other. (ie. over/underpass) When Motorways meet other motorways they generally use ramps that are classified as Motorway Link. These motorways usually connect to other cities or move the traffic around and through a city. Limited access ring roads usually fall in this feature class also.

A trunk is what a motorway becomes when it loses one of it's criteria. This usually occurs to US, State, County highways as they move outside the urban areas. Intersections with other roads can occur at grade and/or when ramps are no longer needed to access the road. Usually they remain 4+ lanes and may or may not be divided by a physical median.

A primary road can be a US, State, County Highway or other road that connects two cities or moves traffic from one part of the city to the other. These are the highways that become Main St when they go through a small rural town. They will have traffic signals when they reach more densely populated areas. These are the roads you jump on when the freeway has an accident and you don't want to sit and wait it out.

A secondary road moves traffic within a city. It would service only a certain area within a city.

A tertiary road connects the residential roads to the higher classes: motorway, trunk, primary or secondary.

Interstates, US Highways, State Highways, and County Highways should be tagged with ref=*. The value of ref should be as follows: Interstates: I ##. US Highways: US ##. State Highways: US:XX ## (where XX is the state abbreviation) or simply ##. County highways: CTH ## or (##).

Exit ramps/slip roads should be tagged as highway=motorway_link or highway=primary_link based on the most significant of the roads they connect. The first node of the exit ramp should be tagged with the highway=motorway_junction tag, with corresponding ref=* for the exit number. In places where a ramped junction is named (such as the High Five Interchange), all ramps should be tagged with name=*.

-- PeterIto 02:57, 23 December 2011 (UTC)

Delaware State Roads

As I noted at United States roads tagging#Delaware, state routes are currently tagged with both "SR" and "DE" type key:ref values. I've been using "DE" and I recently saw one of my tags reverted to "SR". Instead of continuing to edit any of the refs—even though the current state is chaos (see this view and this view). Apparently, the official line in Delaware government is that neither "SR" nor "DE" are to be used on road signage, but that the state roads should be distinguished from US routes by the shape of a white medallion on a black background.

Based on this, I would suggest that we drop all "SR" and "DE" prefixes for the state road segments, leaving them just as the numeric designation.

However, on the associated relation:route, should keep the "US:DE" network designation so that the relation can be properly interpreted in a national network context.

As for county roads, I had written a paragraph on that following the state passage, but then removed it as I couldn't confirm the existence of county road networks by reviewing the state and county government websites and reports. This is _probably_ just my not seeing something right in front of my face, but I want to do some more research before writing a segment on the us roads tagging page. There is a guideline, with an example image, which indicates use of the county name and the alphanumeric designation.

In the event of tagging county roads, such as 17245421 17245421, I would suggest using "ref=Sussex 213" instead of "ref=CR 213" as this would match the published guideline.

In the cases of roads with names like "Road 625", I would suggest our using "Rd 625" instead of "RD 625", as the latter implies two words and the first, one.

Thanks for your feedback. I will post a cross-reference at the Talk:Delaware page.

--Ceyockey 22:54, 28 December 2012 (UTC)

P.S. Of course, the other option is to use "SR" as this is used in Delaware government documents to distinguish from "US", as in page 22 of this PDF. --Ceyockey 23:10, 28 December 2012 (UTC)

States commonly have a policy of using nothing but shields to represent routes but nonetheless use a scheme like "SR 123", "[XY] 123", or "SH 123" to refer to the route in space-constrained, plain-text situations. (On the other hand, some states would just say "Hwy 123".) So how would a variable message board in Delaware refer to the route? – Minh Nguyễn (talk, contribs) 06:37, 29 December 2012 (UTC)

It is important not to confuse local standards for road signs with OSM tagging conventions. We are not erecting road signs and there is no way to represent the shield shape in the ref tag. I would suggest following OSM's standard for US state routes and including the "DE". Then if anyone wants to draw a map with the correct shield, he can detect the "DE", take it off, and replace it with the proper shield for Deleware state routes. TomashPilshchik (talk)

The convention may be to use a state abbreviation in many states, but not in all of them. Mapping communities in some states have gone with "SR 123" or "SH 123" because that's literally the route reference people use every day in speech, writing, and signage. Is ref=* meant to be an OSM-specific code for a highway, or a representation of verifiable ground truth? If the former, we should've stuck with "US:CA 123" to avoid ambiguity! In the past, a big reason for using state abbreviations was so that (say) MapQuest could choose a shield by parsing ref with regular expressions. But now that most states have good coverage of route relations, we should stop encouraging renderers to parse ref this way. It makes shield rendering deceptively simple: maps too commonly put shields in the wrong country, miss the other six common state highway networks in Texas, allow Colorado to annex random counties in Minnesota, and mess up concurrencies. The route relation's network=* tag is the proper place to indicate the state. I suggest leaving ref=* as a human-readable aid, somewhat like is_in=*. – Minh Nguyễn (talk, contribs) 06:53, 24 September 2014 (UTC)

Are folks in this thread aware of this link, OpenStreetMap Foundation's United States chapter Shield Renderer, which renders completely with the 'network' tag using road relations (only)? See Key:network (Highway routes)This is FULLY implemented at the Interstate, US, and State Trunk levels in Wisconsin Wisconsin#Roads to name one state of many. Wisconsin County Trunk Highways and Rustic Roads COULD be implemented if added to their database. This link is the one showing 'rendering using internationally unique network' and not an ambiguous key:ref. The standard I use here is 'For refs on ways, use US 10, WI 110, CTH O, and semicolons in between for concurrencies' (in other words, human readable for stuff that won't render shields in relations). In the relations the standard is explained in Wisconsin/State Highway Relations. Feel free to copy/use. Skybunny (talk) 03:47, 1 October 2014 (UTC)

Forest Service Ref Tagging

Under the "National Forest Service, Bureau of Indian Affairs, Power Administration, and Bureau of Land Management routes" section, it suggests the "ref" tag should equal NFD (number) for Forest service roads. I have never heard this abbreviation (NFD) used anywhere within the Lower 50 of the United States. This appears to be an Alaska phenomenon perhaps from the quick research I've done on the topic? But more commonly used abbreviations for Forest Service roads are FS, FR, and FSR. The most authoritative discussion I've seen on the topic comes from a Google Group in which some USFS gis folks got involved: https://groups.google.com/forum/#!topic/giscolorado/JlGuxQwAH78

FS used in official Forest Service gis databases locally and that'd be my vote.

Footways/cycleways in the US

Apparently path vs footway/cycleway/bridleway is/was a hot topic in OSM, but the whole thing seems very Europe-centric. Footways are a particularly foreign concept to me. Here's how I have been tagging:

• Cycleway: paved paths that are more attractive for cyclists or obviously intended for cyclists than other users. Usually I base this on whether there is cycle-specific infrastructure, like a centerline, bike route signage, roundabouts. Also where there are separate-but-parallel paths designated for cyclists and pedestrians.

• Footway: paved paths between buildings within a complex

• Bridleway: I haven't used this one, but I would only use it within an area designated for horses.

• Path: Everything else, including mountain bike trails, hiking paths, and paved urban paths with the above exceptions.

What I don't like is tagging trails as footways and cycleways based only on signage. One area near to me had otherwise identical trails tagged as footways and cycleways based only on whether bikes were allowed. To me, they should both be highway=path and marked with the appropriate access=*.

Does this line up with what other American mappers are doing?

Dericke (talk) 01:30, 23 September 2015 (UTC)

Using US Highway Functional Classification to tag roads

I would like to propose tagging roads in the United States according to their functional classification (as a minimum level). Each state's roads are measured against this system, and as a result, there would be little confusion as to how each segment should be tagged. Roads tagged lower than their national classification should be the exception rather than the rule

HFC code	Classification	Description	Proposed tag
1	Interstate	The limited access Dwight D. Eisenhower interstate system.	highway=motorway
2	Other freeways and expressways	Limited access, grade separated interchanges and design features of interstates, but not part of the Dwight D. Eisenhower interstate system.	highway=motorway / highway=trunk
3	Other Principal Arterial	Connecting routes between cities and the most heavily traveled cross city routes within urbanized areas that encourage mobility and commercial traffic.	highway=primary
4	Minor Arterial	Shorter trip distances, less traffic and more local in nature than the other principal arterials.	highway=secondary
5	Major Collector	These routes funnel traffic from local and minor collector routes to the arterials. These may directly serve schools, business districts and important public functions.	highway=tertiary
6	Minor Collector	More through traffic than a local road but not as heavy as a major collector. These may directly serve schools, business districts and public functions but less important than major collectors.	highway=tertiary
7	Local	Predominately traveled by those accessing their property, rural farm roads and residential neighborhood roads.	highway=residential
	Non-classified	Road not classified under the NFC. Typical of recently built roads, especially in residential neighborhoods, and private roads.	highway=residential / highway=unclassified / Or as otherwise dictated by road conditions

* Highway Functional Classification codes may also be labeled as National Functional Classification (NFC) Codes, FHWA Codes or HPMS Functional Classification Codes; all refer to the Highway Functional Classification system put forth by the US FHWA.

--StudentinGear (talk) 04:26, 15 February 2019 (UTC)

My view is that trunk roads need not be completely grade separated; they may have at-grade intersections with arterials or collectors but otherwise resemble motorways. In my community there is a six to eight lane business spur of the interstate that is classified as a trunk road in this way. It dwarfs all of the primary roads in the area so I see no better alternative.

I would probably classify a roadway that meets all of the characteristics of an Interstate Highway as a motorway even if such a road is not officially a part of the interstate. US Highway 25 in North Carolina (after it splits from the Interstate) illustrates this. Except for the signs it is indistinguishable from the interstate.

I have mainly been classifying roads as residential if their primary function is to provide access to residences. Otherwise I classify them as minor/unclassified. Most rural farm roads are minor/unclassified in my view. Invidious (talk) 05:53, 30 June 2019 (UTC)

The FHWA Highway Functional Classification system was used indirectly in choosing default highway=* values during the original TIGER import, because that's the only data about road classifications that was available in the TIGER dataset. Since then, the community has intentionally deviated from HFCS, particularly in large cities in the East and West Coasts. There have been several proposals to apply HFCS as a rule over the years, but it isn't as straightforward as it seems, because HFCS on its own simply isn't suitable for OSM's highway=* tag.

highway=* is primarily used for making cartographic distinctions (significance, connectivity) and to a lesser extent for implying build quality attributes (speed, grade separation). There are some commonalities with HFCS, but HFCS is the primary way to assess a road's eligibility for federal and state aid, so the criteria are tailored to that use case. Sure, it's more straightforward to apply HFCS to U.S. roads, because the roads were planned with HFCS in mind. But highway=* is an international system that has to make sense in countries with significantly different road construction standards.

Here are some of the problems with applying HFCS on an ongoing basis:

• highway=motorway is for all limited access, grade-separated freeways around the world, not just those forming a given country's premiere freeway network.
• A partially grade-separated expressway would classified as "Other Principal Arterial" or "Minor Arterial" and thus be tagged highway=primary instead of highway=trunk motorroad=yes. Should the Ohio portion of 114680 114680 alternate between highway=motorway and highway=primary with no highway=trunk segments? Should 44037292 44037292 be tagged highway=secondary even though it's limited-access and grade-separated with freeway-style entrance and exit ramps?
• A typical U.S. Route would alternate between highway=primary and highway=secondary every time it enters and exits an urban area. This is unfortunate for renderers, which typically rely on highway=* to make intercity routes look somewhat coherent without needing to work with route relations.
• Under FHWA rules, an expressway that's in the process of being upgraded to a freeway would remain tagged highway=primary until the very last segment of the route gets upgraded to Interstate standards. Sometimes it takes much longer: 31890090 31890090 was just reclassified as "Other Freeways and Expressways", 20 years after it was built to Interstate standards to replace a surface street. At the time of the TIGER import, it was tagged highway=residential tiger:cfcc=A41 based on an HFCS of "Local".

I do think the HFCS guidebook is a good resource for developing our own independent guidelines for applying the global highway=* tag definitions to U.S. roads. As with HFCS, choosing the right highway=* tag does require balancing many of the same factors. But the output (highway=*) differs in the number of possible values, so we shouldn't use HFCS itself as the sole input. If a data consumer requires HFCS or something directly comparable, then it would be best for us to focus on mapping the individual factors that led to the HFCS classification: route relations, driveways, speed limits, lane counts. That way the data consumer can derive an HFCS-like classification by joining OSM data with a published traffic volume (AADT) dataset.

 – Minh Nguyễn ^💬 22:21, 30 June 2019 (UTC)

Florida-style Tagging Ideas

A lot of the tagging on here seems to be in two groups: Texas and US/SR/CR specific. I disagree with both styles of grading and would like to pitch in with my new ideas.

Motorways

This should be ONLY Interstate freeways, toll or not. Speed limit above 35 mph (because many freeway bridges have a low speed limit.) Link on and off of roads with motorway_link.

Trunks

This should be any road that seems to be a freeway without an Interstate designation. Properties include

• speed limit above 50 mph, 35 on bridges
• divided with a median for at least most of its lifespan
• very few if any at-grade intersections (maximum of about 5 per county)
• no Interstate designation

Also remember that if a trunk has few at-grades for about 5 miles, but for 10 miles it has many, split the way to trunk<freeway properties>-primary<many intersections> or lower. A great example of this is Pineda Causeway.

Primarys

This should be any road that is a major thoroughfare through the city, or links two towns or cities that both of the populations are above 25,000. If it links 3 or more towns, cities, or even hamlets, it deserves the primary tag.

Secondarys

This should be any road that is a major/moderate thoroughfare through the city, or links two towns, cities, or hamlets. If it links two towns or cities with a population of 25,000 or more, it should be upgraded to primary. If it links 3 towns, cities, or hamlets, it should be upgraded to primary. (UPDATE) This could connect two villages with a population of 10,000 or less, as long as the roads both stem off of a secondary+.

Tertiarys

This should be any road that is a moderate/minor thoroughfare through the city, or has many unclassifieds/residentials intersecting it, is longer than the majority of the roads in the neighborhood, and also ends at a road that is graded tertiary or higher. If the road continues past the tertiary+ and then ends at a residential, split the way into tertiary->residential. Also could connect a hamlet to a town, as long as the road starts in the town and dead-ends at the hamlet.

Unclassifieds

This should be any road that ranks lower than a tertiary, but has more businesses/industrials than houses. Also could connect two hamlets, as long as the road starts in one hamlet and dead-ends in the other.

Residentials

This should be any road that ranks lower than a tertiary, but has predominantly(85<%) houses. Speed limit generally 25-35. Note TIGER inputs screwed up and added a lot of residentials, lots of these could convert to unclassifieds. This should also be used instead of highway=service for access to residential roads.

(Unmaintained) Tracks

This should be any dirt road that has fewer than 3 houses on it, or a road through an undeveloped property. Doesn't necessarily have public access. Add tracktype.

Pedestrian streets vs. Foot Paths

Pedestrian streets should only occur in downtown areas, theme parks, and should be as wide as a one-way road at least. See St. Augustine's downtown area for a good example. Foot Paths should be anything else.

Living streets

If the speed limit is unspecified, and the road is paved and ends in a cul-de-sac, use this. Set speed limit to 15. If the road is unpaved yet has a "Slow Children At Play" sign, use this also. Otherwise use residential road.

Service Roads

Any road that is paved and is primarily used for access/parking. If it is unpaved consider using Track.

--Floridaeditor (talk) 16:49, 5 December 2019 (UTC)

Forest Service road access tagging

The current article discusses the USFS published roads that are noted as “road closed” and that these should be tagged “Access=no”. Though these roads are in fact excluded from the official Motor Vehicle Use Maps, only the motor vehicle use is not permitted; non-motorized uses are permitted. From the Access tag page- “If only specific transport modes are forbidden, for example, at a vehicle no-entry sign, use a more specific restriction like vehicle=no or motor_vehicle=no over the general key access.” I suggest the original article should be amended to state they should be tagged motor_vehicle=no to more accurately reflect the available non motorized potential uses of these roads Skunkman56 (talk) 02:04, 24 February 2022 (UTC)