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No thoroughfare to specific road

0

How can I specify that a certain road is not to be used as a thoroughfare to reach another specific road? In Norway there are signs prohibiting cars from using a road as a short-cut to another road(usually a small road through a residential area leading to a major road). I cannot use "access=designated" since the road can be used for all other destinations except that specific road. I have tried to illustrate this with a drawingalt text. A car from the bottom passes a sign indicating that it cannot not continue to the major road(in red) but is allowed to take any of the blue roads. People living in that area(past the sign) are allowed to drive onto the red road.

asked 01 Dec '19, 04:34

Odiz's gravatar image

Odiz
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edited 01 Dec '19, 04:36

2 Answers:

3

I think the closed tagging OSM has for this is the turn restrictions schema. While this can encode the relevant information it might be considered a bit of an "off label use". The description below is closest to the second example of a prohibitory restriction on the wiki page.

Steps:

  1. Split the road at at the sign and the relevant points where the drivers might turn onto the main road.
  2. Add a no_left_turn restriction with: the road before the sign as from, the road(s) traversed to reach the main road as via, and the relevant portion of the main road/sliproad as to.
  3. Add a no_right_turn restriction with: the road before the sign as from, the road(s) traversed to reach the main road as via, and the relevant portion of the main road/sliproad as to.
  4. Repeat for any other approaches with the same restriction.

As some might consider this to be stretching the definition of a turn restriction it might be useful to add a note=* tag to the new relations to help future mappers.

answered 01 Dec '19, 11:06

InsertUser's gravatar image

InsertUser
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Never thought of turn restrictions that way. Will give it a try and see if it works. Thanks.

(01 Dec '19, 12:27) Odiz

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First access=designation is not a thing and is always wrong, what you were thinking of is access=destination

Outside of using *=destination I don't see a way of exactly modelling this with the the currently available tags, as, if I understood you correctly, through traffic is actually allowed for most destinations just not to the main road.

answered 01 Dec '19, 10:43

SimonPoole's gravatar image

SimonPoole ♦
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accept rate: 18%

1

I think it is just about possible if you consider it a pair of overgrown turn restrictions. The required 'via' ways are larger than you would usually expect though. I have no idea if existing software will parse it correctly.

(01 Dec '19, 11:12) InsertUser

A dedicated 'multi-from' and 'multi-to' relation type would be better though.

(01 Dec '19, 16:22) InsertUser

Source code available on GitHub .