I wonder if there is a dataset of protected left turn (a left-oriented arrow) traffic signal? For example, a GIS dataset of the location of traffic lights that have this signal.

I thought this information should be essential and easy to be found. However, after I've looked up many detailed traffic signal datasets (data.gov, OpenStreetMaps, and GIS open data websites), none of them seems to have protected left turn signal information.

If there is no such dataset, what would be the rationale of lacking such data? US data preferred.

  • @Jan Doggen I would say for the US temporarily.
    – Vossk
    Dec 5, 2017 at 22:23

1 Answer 1


OSM has this data, you can search for tags here.
You can read more here: Mapping Turning Lanes in OpenStreetMap, and view key turn's documentation here.
OpenStreetMap's Forum is essentially Stack Exchange for OSM, as well as OSM Slack

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