As one of the developers of the GraphHopper routing engine, I would like to learn what improvements should be made from the point of view of the OSM community. Regarding the routes suggested by GraphHopper on openstreetmap.org or graphhopper.com/maps (no matter which vehicle profiles). I am especially interested in error patterns that happen frequently and in dangerous route suggestions.
There was a lengthy discussion on IRC today about penalties for border-crossings (particularly with respect to avoiding Kalingrad Oblast for travel to Lithuania & Latvia). This may have particular relevance for the UK now. Border facilities are, however, poorly mapped on OSM, and I’m not aware of suitable tags to indicate the length of formalities (e.g., Argentina/Chile crossings on Tierra del Fuego may take an hour: at least on a bus all bags are x-rayed), which likely differ between private & goods vehicles.
Thank you for asking.
The main issue I have with GraphHopper is that it doesn’t recognize U turn restriction when “via” member is a way.
So relation:
type=restriction
restriction=no_u_turn
way (from)
way (via)
way (to)
just doesn’t work.
OSRM doesn’t have a problem with it. But GraphHopper router works only when “via” member is a node.
I wouldn’t say it is simple, but at least conceptionally it is clear how to do it. Still it hasn’t yet a top priority for us and/or our community. If the community wants it we would love to get such a feature :). But as the first contribution this is probably not the best. To get warm with the code and dev tools we have separate issues: https://github.com/graphhopper/graphhopper/issues?q=is%3Aopen+is%3Aissue+label%3A%22good+first+issue%22