User:Trapicki/Proposal Snow Chains

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Draft of Proposal for traffic limitation "snow_chains"

Proposed features/Snow chains

Rationale

This proposal defines keys and values for snow chains (a.k.a tire chains) related restrictions, traffic signs and amenities.

Routing

For routing, it is important to know about existing or possible limitations or equipment that may be necessary, which is especially true for snow chains. As snow chains are only necessary and/or required under certain conditions this may change depening on the time one travels the route, it may even change on short notice during the journey. Knowing the possible limitations beforehand allows to adjust the route or equipment accordingly and consider the implications accordingly.

In case snow chains are compulsory, places to put on snow chains (chain-up area, chain bay) may be shown to help travelers.

General rules for areas/countries, like compulsory winter tires, or requirement to have winter equipment like snow chains availble, or prohibition of use of snow chains, should not be tagged and are not part of this proposal.

Road sign

In Austria[1], Germany, Italy, Switzerland, Czeck Republic and other countries a traffic sign for "snow chains required" exists and is in common use. The UN Vienna Convention on Road Signs and Signals[2] defines a snow chain sign as D, 9 "SNOW CHAINS COMPULSORY" and E, 21 / E, 22 "CHAINS OR SNOW TYRES RECOMMENDED".

Mapping existing things means this has to be mappable, not only the sign but also the restriction on the route.

Current usage

Overpass-turbo: show_chains, snow_chains:conditional, snow_chains:variable, snow_chains:on_demand in overapss-turbo

taginfo:

Proposal

Properties of highway=*

Key snow_chains=*

Values:

In most cases (at least in Central Europe), snow chains will be required conditionally (fixed rule, additional traffic signs) and/or on demand(issued by local authorities depending on actual situation).

Key snow_chains:conditional=*

Standard Conditional restrictions.

Like maxspeed=* usuallly with sign "snowflake", that is, when road is covered in snow or ice, or during a certain time of year.

Examples:

Tagging Explanation Note Image
snow_chains:conditional=yes @ snow; yes @ ice Snow chains required when road is covered in snow or ice.
  • :conditional=* does not allow OR. Multiple conditions separated by ; have to be used.
  • The additional "snowflake" sign[3] requires separate conditions for both snow and ice. Other additional signs may state only snow or only ice.
  • Probably one of the default conditions.

Traffic sign "Snow chains" compulsory beginning with additional condition sign "when ice or snow" at Weinbergweg, Stattegg, Austria
Traffic sign "Snow chains" compulsory beginning with additional condition sign "when ice or snow" at Weinbergweg, Stattegg, Austria
snow_chains:conditional=yes @ snow; yes @ ice; no @ motor_vehicle AND awd AND "driving uphill" Snow chains required when road is covered in snow or ice, but not for uphill driving AWD motor vehicles.
  • AWD here means all-wheel-drive, not limited to offroad vehicles.
Traffic sign "Snow chains" compulsory beginning with additional condition sign "when ice or snow" and "ausgenommen bergwärtsfahrende Allrad-Kraftwagen" ('except uphill driving AWD motor vehicles') at L619 Weinebenestraße near Deutschlandsberg, Austria
snow_chains:conditional=no @ motorcar AND winter_tires Snow chains required, expect for motorcars (Class N) with winter tires.
Traffic sign "Snow chains" compulsory with additional sign "ausgenommen PKW mit Winterreifen" ('except motorcars with winter tires'), beginning.
snow_chains:conditional=required @ (ice AND weight>3.5t); required @ (snow AND weight>3.5t); Snow chains required for vehicles with weight > 3.5 t when ice or snow on road surface.
Trafic sign "snow chains required" with additional sign "when ice or snow for vehicles heavier than 3.5 t" (snowflake and "3,5t") at Pötschenpass, Austria


Key snow_chains:on_demand=*

Deduced from crossing:on_demand=*

Note in progress: maxspeed:variable=* was my first though, but "on demand" is more self-explaining, easier to understand and remember.

  • snow_chains:on_demand=yes - Snow chains required as announced on site. Sign may be flippable, foldable, turnable, covered, removable.
  • Can be combined with snow_chains:conditional=*.
  • If the restriction is permanent, this tag should not be set.

Example:

Tagging Explanation Note Image
snow_chains:on_demand=yes Sign can be rotated.
Traffic sign "Snow chains" compulsory with additional sign "ausgenommen PKW mit Winterreifen" ('except motorcars with winter tires'), beginning.
Sign rotated to right, facing outside of the street to let it have no effect.


Place to put on snow chains

This is probably some easy accessible place beside the road, with virtually no inclination to allow rolling on the car while laying snow chains even in fresh snow. Parking restriction may apply to prevent usage as parking area and thus make putting on snow chains impossible. Known as "chain-up areas", "chain bay"

information sign

As UK snow chains are not needed very often, and because it's actually prosecutable to damage roads with snow chains in the UK, I would not expect to have an established British English term for that.

Examples:

Key/tags tbd. Think about parking restrictions (no parking, no parking when snow chains compulsory...)

Connection to road section tbd.

Road sign

tbd.

See Proposed features/Extended traffic signs tagging

Rendering

Road: For winter theme, add some bold/red/dashed(for "on_demand") highlighting.

Chain-up area: Like parking space, but with snow chain as symbol. Can occur alongside parking sign, if parking is allowed.

Related topics

Open Questions

  • Which countries have decent usage of snow chain sign?
  • How are snow chain signs properly mapped?
  • There are designated places to put on snow chaines, much like highway=rest_area. How to tag them?
    • How to link a snow chains road section to the appropriate "snow chain place"?
  • Should "Road opened or closed" from the Vienna Convention be included?
  • What about "Czech road sign Winter equipment", https://en.wikipedia.org/wiki/Snow_tire#Europe
  • Should the proposal also consider "Winter Equipment", like "Winter tires", or "Snow Studs" (Austria: "Spikes")?

TODO

Before proposing

  • Create proposal in private sub-page (too late...)
  • Ask friendly person for comments

After proposing

After acceptance

References

  1. | StVO §51 lit. b Nr. 22 Gebotszeichen "SCHNEEKETTEN VORGESCHRIEBEN" in RIS
  2. https://treaties.un.org/Pages/ViewDetailsIII.aspx?src=TREATY&mtdsg_no=XI-B-20&chapter=11&Temp=mtdsg3&clang=_en%7CUN
  3. | StVO §54 Z. 5 lit. f "Diese Zusatztafel weist darauf hin, dass das Straßenverkehrszeichen bei Schneelage oder Eisbildung auf der Fahrbahn zu beachten ist." in RIS

Vienna Convention on Road Signs and Signals Anex 3 B.2.(i)
Snow chains compulsory Sign D, 9 "SNOW CHAINS COMPULSORY", shall mean that vehicles travelling on the road at the entrance to which it is placed shall have snow chains fitted to not less than two of their driving wheels.

Annex 5 F.7. "ROAD OPEN OR CLOSED" sign

Sign E, 21, "ROAD OPEN OR CLOSED", shall be used to show whether a mountain road, particularly a section leading over a pass, is open or closed; the sign shall be placed at the entry to the road or roads leading to the section in question. The name of the section of road (or pass) shall be inscribed in white. On the sign shown, the name "Furka" is given as an example. _ 66 _ Panels 1, 2 and 3 shall be removable. If the section of road is closed, panel 1 shall be red and shall bear the inscription "CLOSED1

if the section is open, panel 1 shall be green and

shall bear the inscription "OPEN", The inscriptions shall be in white and preferably in several languages. Panels 2 and 3 shall have a white ground with inscriptions and symbols in black. If the section of road is open, panel 3 shall remain blank and panel 2, according to the state of the road, shall either be blank, or display sign D, 9, "SNOW CHAINS COMPULSORY", or display symbol E, 22, "CHAINS OR SNOW TYRES RECOMMENDED". This symbol shall be black. If the section of road is closed, panel 3 shall show the name of the place up to which the road is open and panel 2 shall display, according to the state of the road, either the inscription "OPEN AS FAR AS", or

symbol E, 22, or sign D, 9 .