Routing/Narrow Roads

A summary detailing how prevalent open-source OSM routers manage navigation on narrow ways and the array of OSM tags they accommodate.

OSRM

The standard car profile:

• will not direct a vehicle along a road with a width<2.2 and a narrow=yes tags
• will adhere to any specified legal max_width
• will impose a 0.5 speed penalty for any way with width<=3, or any way with lanes<=1 that does not have oneway=yes.
• will penalize oneway=alternating by a guesstimated delay of 40%. Some renderers might also draw two-way arrows based on this tag.

Sources:

• https://github.com/Project-OSRM/osrm-backend/issues/6613#issuecomment-1520813631
• https://github.com/Project-OSRM/osrm-backend/blob/master/profiles/lib/way_handlers.lua#L400-L402
• https://github.com/Project-OSRM/osrm-backend/blob/master/profiles/lib/way_handlers.lua#L487-L509
• https://github.com/Project-OSRM/osrm-backend/blob/31e31a63d062fb804f5f4695ed3036ca7a269ead/profiles/lib/way_handlers.lua#L404-L409
• https://github.com/Project-OSRM/osrm-backend/blob/master/profiles/car.lua#L44
• https://github.com/Project-OSRM/osrm-backend/issues/6712

GraphHopper

No support. Currently, width, max_width, andlanes are not taken into account.

Sources:

• https://discuss.graphhopper.com/t/osm-tags-and-penalty-rules-for-narrow-bidirectional-roads/8524
• https://github.com/graphhopper/graphhopper/blob/master/core/src/main/java/com/graphhopper/routing/util/parsers/CarAccessParser.java
• https://github.com/graphhopper/graphhopper/blob/master/core/src/main/java/com/graphhopper/routing/util/parsers/CarAverageSpeedParser.java

Valhalla

Limited support. The standard car profile:

• will adhere to any specified legal max_width
• Currently, width, andlanesare not taken into account.

Sources

• https://github.com/valhalla/valhalla/discussions/4591
• https://valhalla.github.io/valhalla/api/turn-by-turn/api-reference/
• https://taginfo.openstreetmap.org/projects/valhalla#tags
• https://github.com/valhalla/valhalla/blob/5d250d21ad06e396ddb731d471273780bbfa1655/src/sif/autocost.cc#L466

OpenRouteService

Limited support. The standard car profile:

• will adhere to any specified legal max_width
• Currently, width, andlanesare not taken into account.
  

Sources:

• https://ask.openrouteservice.org/t/osm-tags-and-penalty-rules-in-openrouteservice-for-narrow-bidirectional-roads/5794
• https://giscience.github.io/openrouteservice/technical-details/tag-filtering
• https://github.com/GIScience/openrouteservice/blob/main/ors-engine/src/main/java/org/heigit/ors/routing/graphhopper/extensions/flagencoders/CarFlagEncoder.java