Proposal:Lane and lane group

This proposal has been obsoleted by Lanes.

Footway and cycleway lanes next to a vehicle lane

This proposal tries to establish a concept for mapping “lanes” – all sorts of (almost) parallel way parts, such as cycleways, pavements or car lanes.

Objectives

Vehicle lanes with lane-specific turn restrictions

This proposal was set up with the following primary objectives in mind:

Reusing existing tags for maxspeed, access, surface, width …
Specifying full lane ordering. Example: The mapper should be able to not only express that cycleway and footway are both on the “left” side of the street, but also which of the two is further to the left.
Creating lanes with own geometries, e.g. for detailed mapping of complicated junctions.
Creating lanes without own geometries, e.g. for streets with perfectly parallel lanes where separate ways would make moving the street and similar actions unnecessarily difficult.
Compatibility with advanced information, such as lanes that connect to different streets and lane-specific turn restrictions. Example: In some situations (e.g. motorway junctions), it is helpful to know which lanes are intended for traveling straight on and which are intended for leaving the street. Ideally, an OSM-based navigation system could provide lane hints to a driver.

The features this proposal is based on are lanes (as lane ways or lane relations) and lane groups.

A lane way represents a single lane. It is tagged with the key lane and one of the values from the table at #lane values. With the exception of having a lane tag instead of a highway tag, this way can be tagged as usual, e.g. with access=*, surface=* …

A lane relation is an alternative to the lane way. It also represents a single lane, which is assumed to represent a lane parallel to the highway referenced in the lane_group. A lane relation needs no members and is tagged with type=lane. All other tags can be used as if it was a lane way.

A lane_group relation connects a highway and its lanes. It is tagged with type=lane_group and has the lanes and the highway as members (see #lane_group relation members).

The value of the lane-key indicates the type of traffic the lane is intended for.

Value	Description	Implied access information
footway	for pedestrians	`foot=designated`
cycleway	for cyclists	`bicycle=designated`
vehicle_lane	for vehicles such as cars and hgv, by default also for bicycles	`vehicle=designated`
bus_lane	lane where busses can drive and/or stop	`psv=designated`

By default, the lane is not available to any type of traffic that is not listed (access=no).

Note: This list is most probably incomplete and might require changes. Please use the talk page to comment on and discuss these values.

Type	Role	Recurrence	Description
	highway	one	the highway the lanes belong to
	none or number	one or more	lane that belongs to the highway's lane bundle – can be lane way or lane relation Numbering: You may use positive and negative numbers in a lane's role field to indicate their ordering – if lane “a” has a lower number than lane “b”, “a” is farther to the left than “b” (based on highway direction). A lane without number defaults to 0. Since API v0.6, the relation members' order can be used instead of explicit numbering. Lanes are supposed to be ordered from leftmost to rightmost lane.

Description	JOSM view	JOSM lanetool view	File link
two-lane road with a cycleway for each direction and a single footway. The mapper decided to draw one of the cycleways as an own way. The lanes have different surfaces (asphalt, cobblestone on the footway) and widths. See details ...			.osm file
TODO: more examples