Proposal:Tag:service=bus bay

Tag:service=bus_bay
Proposal status:	Draft (under way)
Proposed by:	ManuelB701
Tagging:	service=bus_bay
Applies to:
Definition:	Mark ways solely to access bus platforms (including bus bays).
Statistics:
Draft started:	2024-08-14

The bus stop Sankt Bernhard (eastward) in Mainz. Unlike most bus stops, this one is separated by a traffic island from the rest of the street.

Proposal

The purpose of this proposal is to formally add a definition for service ways which for bus bay which are separate from the carriageway and by extension, any way whose purpose is to access bus platforms. It also includes a better definition to unify the curring tagging practices.

It also includes some synonyms which should be depreacted in favour of standardisation.

Rationale

Currently, bus bays are tagged using bus_bay=* which works for bus bays which are segregated at most — if at all — by kerbs from the main carriageway and appear like street side parking spaces (to the point where they're sometimes reporposed from one), the tagging fails a stronger barrier between the bus bay and a carriageway is used. In that case, the bus bay is its own way and the platform has to be accessed from that way but the current tagging can't reflect this.

The problem right now is that there are different mapping standards to tag bus bays. The following practices have been in use:

• Bare highway=service: An established tag, used for any way whose main purpose isn't transit (i.e. throughfare) and the de jure way of mapping bus bay ways. Generally sufficient the same way parking aisles and driveways can be tagged without service=*.
• Bare highway=busway: A relatively new tag which is used to denote bus-only ways / protected bus lanes but also is used for bus bays, protected or otherwise. Definite misuse for unprotected bus bays and potential misuse because bus bays are not lanes nor fit fit the busway definition for being too short.
• highway=service with service=driveway: Use of the tag is intended to access properties. Potential misuse because bus bay ways don't access properties but also generally lead to dead ends while bus bays continue onwards.
• highway=service with service=parking aisle: Use of a tag is intended to serve access for parking spaces and a bus bay is seen as a type of parking. Potential misuse because the intention is for ways within a parking lot, for ways between parking spaces, but not to the parking lot itself (and for all intents and purposes, bus bays aren't really parking lots).
• highway=service with service=drive-through: Use of tag is intended to access a service (like a shop) from a car. The most fitting option (in that the "service" is a bus platform) but still a potential misuse because the main intention is to access shopts but there is no shop to access in this situation.

Quality assurance like PTNA will complaining about the latter three tags for how unusual they are for busses and how they're unsuited for them.

service=bus_bay covers another relatively common use of service roads while also standardising the tagging practices. As of now, it's been used seven times (including four times by me). Some alternative tags also have been used for similar purposes:

• service=busservice (as of now only used for bus bays)
• service=Bus (used both as busways and bus bay ways, possibly a synonym to highway=busway)
• service=busbay (alternative spelling of the proposed tag, inconsistent with current bus_bay=* tag)

Why not on highway=busway?

The rationale is that busways are essentially bus lanes as separate ways among some other definitions but bus bays by definition are not lanes (nor do they count as proper lanes). For bus bay ways, their main function isn't transit but rather serve an access to bus stops which is consistent of the definition of highway=service. This is particularly notable if express busses exist which never enter the bus bay because they don't serve the stop.

Furthermore, bus bays are to roadways what passing loops (with stops) are for railways and the latter are tagged as service=siding which classifies them as service tracks. The analogy for highways is therefore to treat bus bay ways as service roads and not busways.

One thing what both have in common is that they primarily if not only serve busses and use similar signs (e.g. a blue circle with a white bus under the Vienna Convention).

Why not bus_bay=yes?

The intend of bus_bay=* is to denote whether a highway has a bus bay but not whether a way is a bus bay. In other words, bus_bay=yes has the implication that some bus bay exists along the given highway (albeit without the specification on where it exists exactly) and thus implies the bus bay way has its own bus bay. service=bus_bay lacks this ambiguity. This is similar to the mapping of sidewalks where instead of using sidewalk=yes on footways (which implies there is a sidewalk to the sidewalk), one is using footway=sidewalk instead.

Tagging

General tagging

Draw a highway=service way and add service=bus_bay to it. Due to their nature, most bus bays ways (such as next to to kerbs) also are oneway but exceptions do exist (particularly if the bus bay is in the highway median). The tag implies bus=designated but general access per-se might not be forbidden (this is especially important if the corresponding sidewalk so foot=yes is implied with a sidewalk=yes value but default access if for sidewalk=no/separate values). Optionally draw a barrier (if it isn't handled by e.g. an existing platform already) to denote others that this is a real way and not a virtual way (which did happen a couple times on OSM).

An example of a double bus bay: Every bus stop on a the main trunk (the ways on the rails*) has its own bus bay but moreover, a second bus stop is placed behind. The left way is thus tagged with service=bus_bay, the right one with bus_bay=both

For the way the bus bay is branching off, it does not have a bus bay to its side. Basically, if you were to keep bus_bay=yes together with a separate, one would interpret this that there also is a regular bus bay (i.e. taking shape of street_side parking) in addition to a separate one. This is important because such style of bus stops exists in bus terminals as the image to the right shows it. If a bus stop isn't in shape of stop style, use bus_bay=no.

And speaking of bus_bay for the classic example, you could argue that you can tag the branched off way with bus_bay=separate much like how you can use cycleway=separate for separately drawn highway-adjacent bicycle tracks. However, bus_bay=separate was never formally defined and is out of scope of this proposal and furthermore might not be the best fit in the situation either given that normal bus bays take shape of the aforementioned street_side parking (it's most likely better suited to tag regular bus bays than a separate way, particularly to tell renderers to not draw a separate area for the bus bay).

When to use service=bus_bay

• The most simple case: The bus bay is separated by a barrier e.g. there is a traffic island separating it from the main highway (see example image).
• Median bus stops when not part of a bus lane. For buses with doors on one side, a way inside a median can be only be realised with a bus bay way.
• Ways inside bus terminals. This is the most similar to service=parking aisle. Main transit and general service ways still should be tagged appropriately, though (see below).
  • Most notably, if the platforms are accessed from a public road, all the ways into the terminal are tagged service=bus_bay regardless.

When not to use service=bus_bay

• No clear entrance and exit in which case no way should be drawn at all and bus_bay=* should be used instead:
  • The bus bay is merely a carriageway extension with no (non-paint / -surface) separation. You don't draw extra ways for a new lane, only when a separation exists (see Dual carriageway for more explanation behind the reasoning).
  • Drawing a way into a bus bay whose separation is at most a continuous kerb. Drawing a separate way here also is verboten because no singular way can be drawn (akin to how one doesn't draw a way for street side parking parking but certainly for parking lots). Instead, add bus_bay:side:kerb if you're keen to denote the type of separation.
• They are not an alternative to highway=busway:
  • That means, protected bus lanes still should be tagged with highway=busway.
  • If the supposed "bus bay" actually extends for quite a while (e.g. up to the next stop), it's a proper busway and not a bus bay way (akin to the distinction between long passing loops and proper multi-tracks for railways).
• Short bus-only streets also are excluded in the definition (akin to how you wouldn't tag them with highway=busway.
• Transit malls and other bus-only streets, no matter how short, don't classify as bus bays either.
• Trunks of bus terminals
  • This means, unless the terminal and its platforms are placed right next to an open highway, ways in and out of the bus terminal are generally tagged highway=service (think of parking lots and how the canonical way of using service=parking_aisle is not the ways in and out of the lot).
  • This is particularly true is the bus terminal if placed on a throughfare (open for general traffic or otherwise) where the trunk most likely is tagged highway=unclassified, highway=busway or (sometimes) highway=pedestrian. This should never be changed into highway=service + service=bus_bay.
• If the service road doesn't provide access to a bus stop but (also) for other purposes, the service road is not for a bus bay.

• 

  A simple bus bay in form of cutting inside the carriageway. Because of the lack of barrier, this should be tagged with bus_bay=* and not with its own way.

• 

  This bus stop does have a barrier but merely a (lowered) kerb which doesn't create some sort of entrance at least. They too should also be tagged with bus_bay=*.

• 

  Although this shows a bus stop which is separated by a kerb, for the fact that this continues onwards to the next stop makes it a busway and not a protected bus bay.

Edge cases

There still are cases where it's ambiguous on whether to use service=bus_bay or any other tug such as highway=busway. The purpose of this proposal is to clarify these edge cases before the tag will be used in practice.

(This is one where one should discuss throughout by bringing up pro and contra arguments and might include other cases. Once they've been settled, they'll be included in the respective sections. Voting will start once they've been properly defined.) (I also need some diagrams which show the road layouts as words don't do justice alone. It also allows the use of tagging standards)

Bus loops

Some bus stops are located inside turning loops, typically a semi-circle with a clear entrance and exit. This allows buses to not only get off the main carriageway but also to turn around, combining the function of a turning loop and bus bay into one way. This makes it as the status of a bus bay way question.

However, there also exist turning circles (no barrier) which also double as bus bays and are in the same function i.e. buses leave the driving lanes and can also turn around. Given that service=bus_bay is the way equivalent of bus_bay=*, the definition of these turning loops as service=bus_bay primarily depends on whether the carriageway equivalent are tagged with bus_bay=* or not.

A painted bus lane approaches a platform

Basically, a busway mostly exists as painted bus lanes and thus is part of the highway's carriageway. However, the platforms are built right next to the lanes which provides a barrier between the main highways and the busway, thus temporarily creating three carriageways. This opens up the possibility to use either highway=busway or service=bus_bay in this situation.

Interpretation for highway=busway:

• The way is an extension of a bus lane which now is physically separated
• Even buses which skip the stop still pass by the platform and a lane doesn't suddenly become.
• The platform might have its own bus bay if applicable

Interpretation for service=bus_bay:

• The only reason the ways are separate from the carriageways is because of the platform which makes them bus bays by default
• The short way isn't long enough to be classified as highway=busway
• You wouldn't use highway=busway if there weren't painted lanes either

A short, parallel bi-directional way to the side of a main highway

This small bus station has a parallel road to the main road (focus on the image) and also has its own bus bays. General car traffic (and certain buses) travel on the road on the left side.

The typical bus bay way is a siding way to the side of a highway. Moreover, these are usually one-way but there sometimes are cases where the siding is bi-directional which causes buses on e.g. the left side in one direction will cross with cars which drive on the right on the other side (e.g. 494916789 494916789 is a good example). Such a highway will be tagged highway=service as a siding but the question is whether or not it should also have service=bus_bay.

Interpretation for no service=bus_bay:

• The way might have its own bus bays.
• Buses can use them for transit

Interpretation for service=bus_bay:

• The way solely exists to access bus platforms
• Buses which don't stop there won't drive into the siding either.

Examples

• This way is a classic example of a protected bus bay: It's separate from the main carriageway by a traffic island
• Here, the platform is located on the median of the road but the approach is the same: It allows buses to access the (tram) platform but doesn't allow to drive with trams thanks to the lack of solid surface along the way (these ways naturally should include embedded_rails=tram.

Rendering

A narrow road much like highway=parking_aisle at least for Carto. Bus focused renderers can differentiate them by using a different colour for them, though.

Features/Pages affected

• service=bus_bay: Create page
• bus_bay=*: Add link to service=bus_bay
• highway=busway: Add link to service=bus_bay on the bus bay example of Tag:highway=busway#What is not a busway in place of bus_bay=yes

External discussions

Discourse thread

Comments

Please comment on the discussion page or the corresponding thread in the forums.