Traffic signs give instructions or provide information to road users.
The traffic_sign=* tag is used to map traffic signs such as city-limit signs, speed limit signs, maximum weight signs, or any other traffic signs.
Traffic signs give instructions or provide information to road users. Some traffic signs are only relevant at the place where they're mounted (like e.g. a stop sign - called "point-related" signs from now on), while others affect a section of the road (like e.g. a "no overtaking" sign - called "section-related" signs from now on).
How to map
Point-related signs can be mapped by tagging a node, while section-related signs can be mapped by tagging a way (or area). You may also map a section-related sign by tagging it as a node if you only know where the section begins (but not where it ends), or if you just want to explicitly specify the physical location of the sign. As an example, speed limit signs are actually often tagged as node although they're section-related signs. Keep in mind that additional tagging is necessary to indicate the end of the section in this case.
The implications of a traffic sign should always be tagged on the concerned section of the road itself as well, if there's an established tag available for that purpose. The most prominent example are again speed limits here: always also add a maxspeed=* and a source:maxspeed=sign tag to the road itself if you're mapping a speed limit sign. See below for which tags should be additionally added to the way itself when mapping traffic signs.
As a node
It is possible to use a node which is part of a way, or to create a separate node beside the road. Both methods are used in practice.
As part of a way
Create a new node within the relevant way next to the sign. This method allows software algorithms which operate on ways (like e.g. routing or turn instruction algorithms) to consider the sign. Although the exact physical position of the sign isn't directly mapped in this case, a renderer should simply assume that the sign is located right next to the road.
You can use traffic_sign:forward=* to specify that this particular sign affects vehicles moving in the same direction as the way, or use traffic_sign:backward=* to specify that the opposite direction is affected. (Note that direction=forward and direction=backward have also been used to describe the affected direction.)
It is important to note that the affected direction can only be unambiguously specified by using nodes which are part of exactly one highway=*. Avoid junction nodes and nodes between two ways as well (where they have been split, but are connected by a node). If in doubt, better simply insert a new node into the way instead of using an existing one.
As a separate node
Create a separate node beside the road at the position of the actual sign. This allows to map the exact physical position of the sign, but it is not reliably possible to deduce the affected road or travel direction in this case. Software algorithms which operate on ways (like e.g. routing or turn instruction algorithms) will thus generally not be able to consider the traffic sign, but only the tags of the way instead.
On a way or area
When tagged on a way or an area, the traffic_sign=* tag describes the traffic sign(s) that apply to that way or area. The tag is not meant to mark the actual position of the sign in this case, but the affected way or area instead. It should however be assumed that the physical location of the sign is at the beginning and / or the end of the affected section (but note that the affected section may be comprised of multiple ways within OSM).
You may use traffic_sign:forward=* to specify that this particular sign affects vehicles moving in the same direction as the way, or traffic_sign:backward=* to specify that the opposite direction is affected.
It is common to use both human-readable values as well as traffic sign IDs. It is possible to tag multiple traffic signs. Traffic signs which are related to each other (like e.g. a "no entry" sign plus an "except buses" sign) are separated by comma (","), while unrelated traffic signs (like e.g. a speed limit sign plus a "no parking" sign) are separated by semicolon (";").
|Key||Value||Element||Sign||Comment||Additional tags on the way|
|traffic_sign||city_limit||City or village sign.|
|traffic_sign||maxspeed||Maximum speed sign. Usually tagged as node although they're actually section-related signs.||maxspeed=* + source:maxspeed=sign|
|traffic_sign||stop||Stop sign. Usually tagged as highway=stop instead.||highway=stop (on a node)|
|traffic_sign||give_way||Give way sign. Usually tagged as highway=give_way instead.||highway=give_way (on a node)|
|traffic_sign||overtaking||No overtaking sign.||overtaking=no|
|traffic_sign||maxwidth||Maximum width sign.||maxwidth=*|
|traffic_sign||maxheight||Maximum height sign.||maxheight=*|
|traffic_sign||maxweight||Maximum weight sign.||maxweight=*|
Traffic sign IDs
Signs specific to a particular country should include the appropriate country-specific prefix followed by a ":" and then the sign type.
- the country prefix should be the two-letter code of the country the sign belongs to
- traffic signs should be represented by the official id for that particular sign in your country
- where the traffic sign requires a value, you can supply it after the id using brackets: "[value]"
Lists of the official traffic sign ids
Examples of single values
Belgium Belgian maxspeed zone sign should better be tagged as traffic_sign=BE:F4a
- traffic_sign=DE:240 German sign for access=no+bicycle=designated/official+foot=designated/official+segregated=no
- traffic_sign=DE:274.1 German sign for maxspeed=30+zone:maxspeed=DE:30+source:maxspeed=DE:zone:30
Examples of traffic sign combinations
JOSM has an icon for the value city_limit and also renders icons for the keys maxspeed=*, maxweight=* and maxheight=* even without presence of a traffic_sign=* tag. The three last-mentioned keys use a generic icon, which always shows the same value independent from the actual value specified in the respective tag.
The style Land and Road Attributes currently renders traffic signs for maxspeed and overtaking. For maxspeed the icon shows the actual value specified in the tag.
The following table list some examples together with the actual rendering result in JOSM.
|Tags||Description||Rendering result in JOSM|
|Speed limit of 50 km/h|
|End of speed limit|
|Speed zone with 30 mph|
|Overtaking forbidden and a speed limit of 70 km/h|
|End of speed limit and overtaking is allowed.|