I cannot really see why - this is a route within France and I have setup my local server with france-latest.osm.pbf which is presumably what graphhopper.com uses? This is the with the latest “graphhopper-web-0.6.0-bin”.
update: I’ve fixed the underlying data i.e. made the oneway road fully connected. So re-download and the same route will succeed. So the reason that our defaults do not remove such subnetworks is to improve the data for routing.
This is interesting. I ran a small test on 20,000 locations using OSRM, Graph Hopper and Google Maps. The failures (count):
Graphhoper - 109
OSRM - 2
Google - 0
However, Google have their own map source so we can’t really compare. OSRM snaps to anything from anything so I guess for those locations it snapped to the closest road.