Mapping lane count and turn lanes in Thailand

Hello Thailand Community,

Grab is going to improve the road attributes related to lane guidance. We’ll be reviewing and mapping missing lanes and turn lanes information in major intersections (motorways, trunk, primary, secondary and tertiary).

Regions we are reviewing/mapping:
Starting with the following city [cities]:

  • Bangkok

We’ll be following OSM Key:turn - OpenStreetMap Wiki and Lanes - OpenStreetMap Wiki global and local policies, along with any other guidelines as appropriate.

Apart from the tags that refer to turn lanes and lane count information, in some specific situations, we will also use:

  • change:lanes=* on the OSM way, to indicate that there is a lane change restriction, as described here
  • lane_markings=no on the OSM way, for existing information, where there are no markings that separate the individual lanes of the road.

Plugins & Paint Style : Turn Lane Editor, Lanes and Road Attributes map paint style.

Please feel free to reach out to @GRABOSM , @mapdevsaikat, @daniela-rus for any further queries & suggestions.


@Saikat_Maiti Not related to main highways as described in your campaign, but I’ve come across new information suggesting that borderlines cases (e.g., <=4 meters) do not need to use a lanes=* tag regardless of markings on the ground.

Instead, it would be recommended to use lanes_marking=no + width=X + source:width=estimated.

For more details, you can refer to this global voting topic at: When should the 'lanes=*' tag be applied?

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Hi @julcnx, thank you for sharing the borderline cases with examples. I have updated the team regarding the policy.