Speed Limits

I apologize in advance, I am very new to OpenStreetMap and open source in general. I work with a transportation company and we have GPS in our vehicles. One of the features of the GPS is monitoring vehicle speeds to ensure our drivers are driving safely. We set parameters based on common sense, not just the speed limits. However, I have noticed the speed limits on our roads are quite often off, or at the most “estimated.” My GPS vendor said they use OpenStreetMaps for this information and suggested if I want it more accurate, I should edit the maps to include the speed limits. So here I am…

The biggest issue I am facing is the length of the road segments. Some road segments include portions where the speed limit is 50, while other portions of the same segment have a speed limit of 80. I assume I need to split the segment to make the speed limits accurate, I just can’t figure out how to make this happen. How do I split the segment? Thanking you in advance…

Which editor are you using? I am not that familiar with iD, but in JOSM you simply put a node/point on the road where you want to split it, then select then node and the “P” key will split the road at that point. (At least I think it is the “P” key, muscle memory in my fingers does it without me thinking.)

If you go to openstreetmap.org and click on edit, that will get you the iD editor.

In it, you look for the road you’re interested in. If you’re lucky, there will be a node (point) right where you want to change the speed limit. It may or may not represent a split in the segment (it could be something else), if it’s not you need to create a split there (see below),

If there isn’t a point where you want it, you can add it by double-clicking at the relevant place on the road.

To split a segment at a point, right-click on the point and you should get a mini-menu pop up with 4 items, you want the scissors.

Once you’ve split the segment, click on it to highlight it and check the highlighted bit is correct. Then you can set the speed limit in the left pane.

If you’re using potlach (deprecated) then you’ll have to wait for somebody else to answer.

Remember, the undo button at the top of the window is your friend. :slight_smile:

Yes, P for sPlit in JOSM.

Thank you for the help. Next question: I am trying to add the speed limits for a an area approx 1500 sq KM. Lots of roads that don’t have accurate speed limits in this area. Is there a quicker way than clicking on each road/tag individually? If, for example, there is a way to upload a spreadsheet of data, does it need to be in a specific format?
Thank you again!

How have you got this data. The limiting factor is normally visiting the roads, and checking, rather than the data. Are you sure that you have the right to use the data on OSM.

This sounds like a bulk import and there are special rules for getting those approved.

Maybe you could upload these Gps traces to Openstreetmap.org. This will help other contibutors (or, for that matter, maybe some automated QA tool) to find the places where the limit as specified in OSM data does not seem.to coincidence with how fast the vehicles actually go.

Low results just mean congestion. Slightly high speeds will be normal. Very high speeds may just mean a lack of enforcement in the area.

Keep in mind that the default unit is Km/h. If your values are in mph you should make them explicit. https://wiki.openstreetmap.org/wiki/Maxspeed