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Red is not allowed because after the turn it's restricted to the 1st lane until it passes the yellow entrance. Only green is allowed. How should the turn restrictions be added to this junction?

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asked 05 Jul '21, 17:55

rafaelmartinsrm's gravatar image

accept rate: 0%

edited 05 Jul '21, 19:26

The best way to do this may depend on what you mean by "it's restricted to the 1st lane until it passes the yellow entrance".

If you mean there is a physical barrier between the lanes then it may be acceptable to re-work the junction to attach the yellow slipway east of the route in red.

If there is no physical barrier then you will need to use a turn restriction relation. To me this looks like it would be a restriction=no_left_turn relation between the road segment just after 1 to the road segment 2 is on via the curve shown in red and the section shown between the prohibited U and the yellow.

If the distance was small enough you would be able to edit this using iD's built in turn restriction editor by selecting the node where the illegal turn begins, increasing the 'distance' and 'via' sliders to show the full turn and selecting the origin and prohibited destination.

If the distance is too big you will have to split the ways and create the relation manually. This is a bit tricky in the 'default' iD editor as the way it presents them is reversed for the way they are actually stored. It is workable with a bit of persistence, but they are much easier to edit in something like JOSM (see this page for guidance).

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answered 05 Jul '21, 19:05

InsertUser's gravatar image

accept rate: 19%

I added a photo showing the phisical barrier between the lanes, preventing the driver from turning right on the yellow entrance.

(05 Jul '21, 19:27) rafaelmartinsrm

If this barrier exists all the way back to the U loop then it is probably OK to disconnect the way and reconnect it after the yellow turnoff. The posts being in a continuous stretch of asphalt makes it a little arguable, but I think it's reasonable here unless there is a local convention to do otherwise. It may be worth mapping the barrier separately as a signal to other mappers not to revert the change on the basis of a blurry satellite view.

(05 Jul '21, 20:25) InsertUser

Note: I like iD editor for mapping turn restrictions. It is simple, I find other editors difficult for this task.

(06 Jul '21, 09:34) andy mackey

I realised that InsertUser's the answer was the correct one. I wanted to point other mappers struggling with turn restrictions that iD is easy to use. If they did a search for a solution my comment may help them.

(06 Jul '21, 13:58) andy mackey

@jmapb iD has a slider to allow you to use up to 2 via ways if needed. You do need to initiate the turns restrictions interface by selecting the first node of the turn though.

@andy I was able to find this junction in OSM, unfortunately iD's max search radius (50m) is too small to use their rather neat interface at this location.

(06 Jul '21, 14:44) InsertUser

@InsertUser Oh, news to me! I'll try it sometime. Zapped my comment to avoid any confusion.

(06 Jul '21, 15:38) jmapb
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question asked: 05 Jul '21, 17:55

question was seen: 890 times

last updated: 06 Jul '21, 15:38

NOTICE: is no longer in use from 1st March 2024. Please use the OpenStreetMap Community Forum