Autorouting on "Sparrendreef" between N51.56148 E5.15524 and N51.56121 E5.15543 refuses in both directions.

I drove this road today by motocycle, didn't see a reason for that refusal.
Garmin's CityNavigator does route here.

I drove on the B257 coming from South on 2017-07-13 and wanted to turn left onto the marked road towards Kottenborn.
Unfortunately it is forbidden to motortraffic.

A recent download of the Motoroute_OSM map (GeoFabrik) allowed routing for car/motorcycle.

The road/traffic sign "round white with the red border" (model C 01 in the Netherlands) is placed at it's beginning.

Any 'mapper', thanks for appending this information.