Weird behavior on fresh installed local server

Open Source Routing Engine
1

Hey graphhopper team !

I’m facing a simple problem with a fresh installed Graphhopper server (v11.0), default route sometime prevents tunnels and bridges from main road.

For example : from 49.42621053,1.105771538 to 49.437094,1.109994

On my fresh installed server :

2026-05-25_19-26
2026-05-25_19-261349×1134 411 KB

On official server :

image
image1004×1159 228 KB

Section inside the red square is a tunnel.
The official Graphhopper server is right, the tunnel is the obsious and shortest way :+1:

Other example : from “Bergen op Zoom” to “Goes” , around 51.423771,4.188086 location, route leaving motorway (to avoid a bridge/small tunnel ?) and then go back on motorway.

image
image2227×579 246 KB

On official server :

image
image2221×547 238 KB

Grapphopper’s config

graphhopper:

  datareader.file: ""
  graph.location: graph-cache

  profiles:
    - name: car
      custom_model_files: [car.json]

  profiles_ch:
    - profile: car

  profiles_lm: []
 
  graph.encoded_values: road_class,road_class_link,road_environment,max_speed,road_access,surface,smoothness,max_width,max_height,max_weight,hgv,max_axle_load,max_length,
             ,lanes,osm_way_id,toll,track_type,country,curvature,average_slope,max_slope,car_access,car_average_speed

  graph.elevation.provider: srtm

  graph.elevation.cache_dir: /elevation/srtm/

  prepare.min_network_size: 200
  prepare.subnetworks.threads: 1

  routing.snap_preventions_default: ferry

  routing.non_ch.max_waypoint_distance: 2000000

  import.osm.ignored_highways: ''

  graph.dataaccess.default_type: RAM_STORE

Am I missing something ? Is there some extra configurations on official Graphhopper servers ?

Thanks a lot !

2

Hi,

please look on the involved OSM ways when debugging such issues. Often speed limits or access restrictions are the reasons for “weird” routing results.

Please also keep in mind that the version at graphhopper.com is not identical with the open source version. It has different rules to calculate the “average speed” of the chosen vehicle type.

You can inspect the parsed speed limit and estimated speed in the elevation graph at the lower bottom of the web frontend.

That’s a data issue. The main road has `maxspeed=50` in the tunnel while the parallel overground road already has `maxspeed=70`. GraphHopper chooses the faster route (it is about 4 seconds faster).

Reason: The link has a higher speed limit.

Solution: Use a custom model to de-prioritize the link if this issue bothers you.

{
  "priority": [
    {
      "if": "road_class_link",
      "multiply_by": "0.9"
    }
  ]
}

Best regards

Michael

3

Woaw ! Realy complete answer, thank you so much @Nakaner_Geofabrik for this priority tip :sparkles:

I will keep an eye on OSM data for speed limits in the futur :wink: