Hi,

On Sun, Nov 24, 2013 at 12:32:35AM +0100, Michael Kleidt wrote:

I found some wired routing on detailed mapped crossings like http://osm.li/2E Instead of simply using way http://www.openstreetmap.org/browse/way/58591662 and way http://www.openstreetmap.org/browse/way/44850965 it looks like the routing tries to avoid the traffic light http://www.openstreetmap.org/browse/node/255758805

I'd say in that case that the traffic lights are not mapped completely. Can you really take the route suggested by OSRM without crossing traffic light?

I don't really know what the best solution is for mapping traffic lights in such a complex intersection, probably putting them where they really are, i.e. in front of the intersection. Not sure what the wiki has to say about that.

One solution would be to add turn restrictions. There are about 10 "crossings" where you can't turn left or right. We would need at least 2 restrictions on each of these points.

An other solution is to ignore traffic lights in routing or add a penalty for each turn, because you normally have to slow down.

I've done just that now. It just went live together with the latest version of OSRM. I haven't extensivly tested if the penalty value is well chosen so let me know when you find that other routes now suddenly become strange.

Or is there a "better" way for mapping big crossings to avoid such indirections?

How about not connecting left-turn lanes and the main lanes they cross? I don't think there is any legal means to do these turns and no real reason to make them routable.

Gruss

Sarah