Traffic lights with radar

While starting a comment to my answer above answer I came upon a new angle I had not looked at before. The Enforecment Wiki page lists a role "force" that I had never used before. Unfortunately, it is very ill documented, none I asked could help me with it and actually it is very rarely used. To my understanding it is intended for our case, though, i.e. for a case where there is an immediate enforcement opposed to a delayed one (e. g. a fine).

Here is an example of such enforcement relation: Relation 8467264

I try to figure that into my answer and how to do that in iD:

There are two cases. 1) you have a speed camera plus traffic lights, 2) you only have traffic lights.

For 1): As for any enforcement relation you need to set up a couple of nodes, in this case four:

#1: the "device" is a point, probably next to the road, where the speed camera is situated

#2: the "force" is a point on the road where the traffic lights stop the traffic

#3: "from" is a point on the road, somewhere in the direction the traffic is coming from. This could be the place of the speed limit sign.

#4: "to" is a point somewhere in the direction the traffic is going to located after the points #2 and #3.

For 2):

#1: the "device" is a point where the measurement is taken. If you don't know where that is, I would put #1 and #2 at the same location.

#2: the "force" is a point on the road where the traffic lights stop the traffic

#3: "from" is a point on the road, somewhere in the direction the traffic is coming from. This could be the place of the speed limit sign.

#4: "to" is a point somewhere in the direction the traffic is going to located after the points #2 and #3.

Now in iD you have to do the following: First create the four nodes if you don't already have some of them. I assume you know how to do that.

Select the first node (#1). In the left pane scroll all the way down to the section "All relations". Klick the big plus (+). Klick "new relation.. " Select "relation" from the bottom. Still in the left pane: enter a name for the relation and enter "enforcement" as the type. A bit down you see the section All members and there it lists the previously selected node. Wher it says "role" in grey color write "device".

Now select node #2. On the left pane scroll down to all relations again and click the plus. Instead of "new relation..." now select the name of the new one you just created. In the "role" field enter "force".

Repeat that for nodes #3 and #4 with the roles "from" and "to" respectively. In case of case 2) above where you don't know the measuring device location I would normally recommend to enter the #2 node twice to the relation. It seems you cannot do that with iD. In that case leave just create a separate node close to #2.

As a last step click on the relation name on the left bottom and delete the name from the name field again. Such relation usually doesn't have a name so we shouldn't invent one. Putting one in in the beginning helps navigating in iD, though.