Lanes
 Feature: Lanes
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| Description |
| To tag individual lanes of a road together with their distinctive properties. |
| Tags |
| turn:lanes=*, destination:lanes=*, access:lanes=*, ... |
This article describes how to tag individual lanes of a road. To tag only the number of traffic lanes, see the key lanes=*.
Contents |
Description
To tag individual lanes of a road together with their distinctive properties the key-extension :lanes can be used.
Lane-specific information can be expressed on a way by suffixing the key with :lanes. This suffix is applicable to any existing <key>=<value> tag pair. In such case, the value of that key then contains the values for each lane separated by a | (vertical bar) in left-to-right order as viewed in the respective driving direction of those lanes. If the value of a specific lane is left blank, the (possibly assumed/implicit) value of the main key without :lanes-suffix applies (the so called default value).
In the common case of two driving directions either :forward or :backward is added to the end of the key; i.e., <key>:lanes:forward describes the properties of the lanes in the same direction as the osm-way, whereas <key>:lanes:backward described the properties of the lanes in the opposite direction of the osm-way.
Examples
In principle every tag used to describe properties of a road can be extended by the :lanes suffix when its value depends on the lane. Following list gives an overview of potentially useful combinations and a short description when they might be needed:
| Road property | Lane specific key | Description |
|---|---|---|
| access=* | hgv:lanes, bus:lanes...
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Useful if access depends on the lane: For example lanes can be restricted to buses (bus:lanes) or forbidden for heavy good vehicles (hgv:lanes).
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| maxspeed=* | maxspeed:lanes
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Can be used for roads where the maximum allowed speed depends on the lane. See example below. |
| turn=* | turn:lanes
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Allows description of designated turn lanes or which lanes will merge in the direction of travel. See detailed examples below. |
| minspeed=* | minspeed:lanes
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Useful for roads where some lanes require a minimum speed or where lanes have different minimum speed. |
| surface=* | surface:lanes
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Lane dependent surfaces, for example if there is cobblestone on the outer lane |
| destination=* | destination:lanes
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While the road specific key describes the direction of the highway by using the name of the city the highway is heading to, the destination:lanes allows tagging of cities when sign-posted for individual lanes. See destination=* for examples.
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| width=*, maxwidth=* | width:lanes, maxwidth:lanes
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Where deemed necessary, the width of individual lanes can be tagged. According to the existing tagging practice maxwidth:lanes would describe a legal width restriction, width:lanes the actual width of a lane.
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| hov=* | hov:lanes
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If one or more lanes of the road are restricted to high-occupancy vehicles (typically vehicles with 2+ occupants, although this varies by jurisdiction). Most useful if entrance/egress is permitted at any point along the route; if entering or exiting the HOV lane(s) is only permitted at certain locations, modeling the HOV lane(s) as separate ways is preferable. |
Different maxspeed per lane (with/without default values)
A simple lane dependent maxspeed example with road sign (one-way street and a general speed limit of 100 assumed):
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Without the use of default values:
lanes=3 oneway=yes maxspeed:lanes=100|100|80 |
Using default values:
lanes=3 oneway=yes maxspeed=100 maxspeed:lanes=||80 |
Considering backward compatibility it might be preferred to tag this using default values.
Two driving directions
In the common case of two driving directions either :forward or :backward is added to the end of the key.
lanes=6 lanes:forward=3 hgv:lanes:forward=no|yes|yes hgv:lanes:backward=no|yes|yes
This is a road with three lanes in each direction and heavy good vehicles are prohibited on the leftmost lane in each direction.
Please note that the lanes are viewed in the respective driving direction; i.e., hgv:lanes:forward describes the lanes in the same direction as the osm-way and the first lane-value refers to the leftmost lane in this direction, whereas hgv:lanes:backward describes the lanes in the opposite direction of the osm-way and the first lane-value refers to the leftmost lane in that direction.
Minimum speed
Road with a sign-posted minimum speed, which applies to one lane only. Can be tagged as:
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lanes=3 lanes:forward=2 minspeed:lanes:forward=50| |
Please note the final | character in the value of minspeed:lanes:forward: Because the right-most lane has no minimum speed, no value should be tagged after the lane separator.
Motorway
The following example demonstrates tagging of a motorway.
lanes=3 destination:lanes=A|A;B|B *
lanes=3 turn:lanes=slight_left|slight_left;slight_right|slight_right *
lanes=3 turn:lanes=slight_left|slight_left;slight_right|slight_right * destination:lanes=A|A;B|B *
lanes=4 turn:lanes=slight_left|slight_left|slight_right|slight_right destination:lanes=A|A|B|B
lanes=4 **
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- Up
lanes=2
- Down
lanes=2 turn:lanes=none|merge_to_left
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- Up
lanes=3
- Down
lanes=1
* These tags show how to add more than one value to a single lane, by separating those values with a ; (semi-colon).
** There is no physical separation between the upper two lanes and the lower ones, just a double solid line. While the editing standards recommend to split the ways only when a physical separation is present, in many regions the ways are already splitted in case of a legal separation like a double solid line. In such a case both resulting ways should be tagged with lanes=2.
Editor support
JOSM
The style Lane and Road Attributes visualizes, amongst others, a variety of lane-dependent tags directly while editing, and also detects some common tagging mistakes like e.g. inconsistent number of lane-dependent values. The image below shows a road tagged with the keys turn:lanes=*, width:lanes=* and placement=*.
See also
- lanes=* for tagging the number of traffic lanes
- turn=* for turn lanes
- destination=* for describing the direction of the highway
- The proposal for the :lanes extension
