This is a typical 4-ways junction with slip roads for each way: https://www.openstreetmap.org/#map=18/4.90865/114.90912 I added some turn restrictions at this junction over a week ago with some visual help from JOSM graphview plugin, but according to map.project-osrm.org they don't work right. I added 4 no_u_turn and 4 no_left_turn for each way, but OSRM says yes_u_turn and allows a roundabout movement to make a left turn. How do I do this right? asked 14 Nov '14, 10:05  raito closed 22 Nov '14, 05:04 showing 5 of 7 show 2 more comments |
The question has been closed for the following reason “The question is self-answered.” by raito 22 Nov ‘14, 05:04
2 Answers:
Try Mapquests router, they are the only ones that consider restrictions where via is a way: answered 15 Nov '14, 07:34  Janjko |
Hey guys, I think I've just found the answer to my own question/problem! The problem was that most (if not all) routing software can't handle ways as via. And the solution is simply making the junction as only one node.. Here is my first one-node junction → changeset 26891534. I will wait for this update to show on the routing softwares mentioned in this discussion, and test this junction before closing this question. Though they will probably now understand my restrictions, but I'm also interested how they will describe the turn directions ("go straight", "turn right", etc) as now the road that used to go through the junction straight is now not so straight. answered 19 Nov '14, 18:13 raito |
you may have read my question https://help.openstreetmap.org/questions/32420/turn-restrictions-and-routing-engines osrm does take a while to update. mmds comment shows how to see date of osrm data
data: 141113 03:59Z That's like yesterday. I made the turn restrictions over a week ago. So most probably I did them wrong.
I can see the no left turns but i cannot see the u turn restriction in edit mode. and as you say OSRM does treat this as a square roundabout. Is that illegal? I assume the junction does not have right turn restrictions? but does have U-turn restrictions, is that correct?
Yes no right turn restrictions, and U-turns at traffic junctions are illegal generally in the whole country AFAIK.
My guess is neither the editor or osrm can handle multiple way vias, as mentioned in note 3 on the relation page https://wiki.openstreetmap.org/wiki/Relation:restriction#cite_note-3 (I was unaware that any ways were allowed in the via role - when I last looked it was just from way, to way, via node). So I think your u-turn relations such as https://www.openstreetmap.org/relation/4166014#map=19/4.90854/114.90943 are correct as per the wiki. Ah - known issue https://github.com/Project-OSRM/osrm-backend/issues/483
That's too bad.. Hope OSRM supports via way soon.. So, am I right to think that I did nothing wrong after all?
More bad news: OsmAnd (my preferred mobile app for OSM) routing also doesn't understand the restrictions.. (new map update 14Nov2014)