Proposal:Turn signals

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Turn signals
Proposal status: Abandoned (inactive)
Proposed by: Biff
Tagging: traffic_signals:turn=*
Applies to: node
Definition: tag for a turn signal

Draft started: 2016-06-16


This proposal describes how to use traffic_signals:turn=* to tag turn signals.

A lot of similarity exists with the existing definition of the :turn suffix (see turn=*).

The proposal also provides a solution for tagging of the information provided by additional signs like "no turn on red".


This information can be used by a navigation system to remind the driver that a separate turn signal exists at the crossing. This can be very helpful for drivers who don't know the area and might not notice the turn signal.


Turn signals are very common. Taginfo currently counts almost 30k traffic signals. It is likely that several hundred to several thousand of these traffic signals have separate turn signals.


The general syntax of the tag is as follows (fields in square brackets [..] are optional):

traffic_signals:turn[:<transportation mode>][:<direction>]
  = <turn-value>[;<turn-value>][|<turn-value>][|<turn-modifier-value>]


Transportation mode

This key-part specifies the vehicle category or transportation mode to which the traffic_signal applies, e.g. bicycle, motor_vehicle, foot, agricultural.

See Key:access#Transport mode restrictions for the full transportation mode hierarchy.


Traffic signals are typically direction-dependent. Use forward and backward to indicate in which direction the restriction applies. The value depends on the direction in which the way is drawn in OpenStreetMap. For guidance on how to identify this in your editor, see the description of the terms "forward", "backward", "left", and "right". This key-part can be omitted in the case of a oneway road.



Many values of :turn are re-used with the addition of the value "all", see below.

<turn-value> Description Example
all normal traffic light without any turn indication Traffic lights 4 states 3.png
left left turn (only) Gruener Pfeil-L.svg
through going straight through (only) Gruener Pfeil-G.svg
right right turn (only) Gruener Pfeil.svg
reverse reverse/U-turn (only) Signal korea 4green and left Turn and U-turn 2.JPG apparently, such specific traffic signals exist in South Korea (topmost light in picture)

To tag what is shown by several traffic lights, the vertical line "|" and the semicolon ";" can be used as follows:

  • The semicolon ; separates values if more than one value apply to one traffic signal.
  • The vertical line | separates values if several traffic signals are present.

It is common that several identical traffic signals are installed. This is typically done to ensure good visibility in all conditions and does not assign traffic signals to specific lanes. If several identical traffic signals are present, each kind of traffic signal is only tagged once. E.g. do not use traffic_signals:turn=left|left|right|right, instead use traffic_signals:turn=left|right. A left to right order (left|through/all|right) should be used.

Please note that the vertical line "|" does not indicate per lane signals, and the :lanes suffix (see Lanes) is typically not used. (If needed, an extension like traffic_signals:turn:lanes:forward=* would probably be possible, but it's not part of this proposal.)


<turn-modifier-value> Description Examples
right_on_red right turn on red is permitted
left_on_red left turn on red is permitted
none_on_red turn on red is not permitted
not_right_on_red right turn on red is not permitted
not_left_on_red left turn on red is not permitted

Please tag only what you can see. Especially rules for turning on red should only be tagged if a relevant sign exists - don't tag the default rule that is provided by local law.


Traffic signal only for traffic that turns left

Sunnyvale left turn light 2.jpg
  • Create node on highway at the stop line. (Don't tag the node where two highways cross.)
  • Tag the node with highway=traffic_signals.
  • Add traffic_signals:direction=forward (or backward). This is not needed in the case of a one-way road.
  • Add traffic_signals:turn:forward=left. A traffic signal is only present for traffic that turns left! There is no traffic light for the general traffic that passes straight ahead over the crossing and the general traffic does not have to stop at the stop line. This is only possible because the traffic that turns left enters a one-way street. Of course this is a very rare case - but it started the idea for this proposal. Since this is a rare case, it might be a good idea to add a note=* that explains the situation. (The picture was taken in a different place.)

Normal traffic signal for all traffic

Traffic signals for all traffic plus a separate signal for traffic that turns right

Traffic signals for traffic that turns left or passes through plus a separate traffic signal for traffic that turns right


Right turn on red

Grüner Pfeil.jpg

Traffic signal only applies to a specific transportation mode

Gruener Pfeil-Rad-R.svg

You can use the applicable suffix for the transportation mode, e.g. if there is a bicycle lane on the highway and a specific traffic signal exists only for bicycles that turn right then you can use the :bicycle suffix to create the tag traffic_signals:turn:bicycle:forward=right.

Right turn on red for bicycles


The sign shown in the image has only been proposed and does not (yet?) exist on public roads in Germany. However, similar signs may exist in other countries. Such signs could be tagged by first tagging the general traffic signals and then adding the specific traffic signals that apply for bicycles, e.g. traffic_signals:turn:bicycle:forward=all|right_on_red.

Related Cases

  • For turn restrictions that are independent of the traffic signals, e.g. "no right turn", see Relation:restriction.

Current usage


Applies to

This proposal only applies to nodes.


The information captured by this proposal is probably too detailed to be shown on a map.

A navigation system might show traffic lights with solid red/yellow/green lights or colored arrows as appropriate.

Features/Pages affected

External Discussions


Please comment on the discussion page.