Hi there.

I've been trying to tag traffic lights which are activated by radar, i.e., above a certain speed limit, the traffic light turns red. What's the correct way of tagging this?


asked 09 Sep, 17:17

AntMadeira's gravatar image

accept rate: 0%


In this case, it doesn't have a display. Just a sign indicating a speed limit ~200 m before. The traffic light is similar to a normal one, but it is activated by radar. Here in Portugal, there are thousands of them. Here's an example: Traffic lights: alt text

and the sign some hundred meters before: alt text

(09 Sep, 17:50) AntMadeira

Just to add one thing - it's clear from the first photo but may not be obvious at first glance - there's no junction associated with (many of) these lights. The aim is to delay speeding drivers for longer than it would have taken to drive slower and smoothly.

(based on my recollection of driving in Portugal some years ago)

(09 Sep, 18:59) SomeoneElse ♦

Do you mean something like highway=speed_display that changes colour when you go above a certain speed?

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answered 09 Sep, 17:43

InsertUser's gravatar image

accept rate: 20%


No the OP does not. Radar activated traffic lights are very common in certain parts of Spain. If the speed detected is higher than the speed limit the traffic signals change to red. In conjunction with traffic calming measures (humps, tables etc), these reduced dangerous speeding traffic to such an extent that much more expensive measures (by pass roads) were not needed.

(09 Sep, 19:05) SK53 ♦

Sorry, I've replied to myself, but it should have been here.

(09 Sep, 19:36) AntMadeira

No matter I've been puzzled about how to map them for years.

(09 Sep, 21:00) SK53 ♦

In that case, the closest I've heard of is traffic_signals=ramp_meter or =controller. The talk-pt mailing list would be the next port of call, but failing that might be time to make something up. highway=traffic_signals+traffic_calming=traffic_signals might be a good start.

(09 Sep, 23:02) InsertUser

I would tag the signal as highway=traffic_signals and then invent maybe a traffic_signals=speed_meter. Additionally, it would make sense to add an enforcement relation: type=enforcement and enforcement=maxspeed, add the traffic signal node as role device. Data consumers might misinterpret that as a speed camera, though, when they do not check what object the device really is.

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answered 13 Sep, 16:24

TZorn's gravatar image

accept rate: 15%

From what I was told at talk-pt mailing list, the best solution would be an enforcement relation between traffic_signals and a radar. The problem is I would need to add a point for the radar and I don't know where the radar is positioned. I would have to guess its position, which I believe isn't the right way to do this... It's a real bummer because there are literally thousands of these radars all over the country.

(13 Sep, 21:07) AntMadeira

With a standard speed or red light camera we only include the camera itself in the enforcement relation not the position of the measuring device. Usually, that is close by anyway. So I don't see why we should handle it differently in this new case.

(14 Sep, 09:29) TZorn

Can you please give me a resume of how I can do that?

(16 hours ago) AntMadeira

The general description of enforcement relations is in the wiki. If you tell me what editor you are using (iD, JOSM?) I can guide you through creating one.

(16 hours ago) TZorn
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question asked: 09 Sep, 17:17

question was seen: 216 times

last updated: 16 hours ago

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