Routing for emergency vehicle

[scottclarke]

I’m trying to use graphhopper to plan routes for our emergency service response cars that use motorway access gates and service routes. I’m very new to Java - I’m just trying to see if I can do a proof of concept to take to my bosses so we can engage with a programmer.

I’ve successfully installed a local java installation from source and can use it to create standard car routes. I’ve tried editing the restricted values section of CarTagParser.java to:

    restrictedValues.add("agricultural");
    restrictedValues.add("forestry");
    restrictedValues.add("delivery");
    restrictedValues.add("military");

    restrictedValues.remove("emergency");
restrictedValues.remove("private");
restrictedValues.remove("no");
restrictedValues.remove("restricted");

I’ve also removed the recent update which restricts access for cars to service roads with emergency access.

I’ve deleted the files in graph-cache and then re-started the application without any success.

Here are two different examples of the access routes, one that includes the tag emergency: designated and one that just appears as a service highway.

Way: 594570570 | OpenStreetMap

Way: 566727987 | OpenStreetMap

When I select the local MVT layer, no overlay or information is displayed for these roads - could it be that they’re not being recognised by the OSM reader?

[karussell]

Instead of changing the CarFlagEncoder I recommend to use the new RoadsFlagEncoder instead and then restrict access as you need it. E.g. using a custom_model like:

{
 "speed": [
  {
   "if": "true",
   "limit_to": 130
  },{
   "if": "road_class == RESIDENTIAL || road_class == SERVICE",
   "limit_to": 30
  },{
   "if": "road_class == UNCLASSIFIED",
   "limit_to": 40
  },{
   "if": "road_class == TERTIARY",
   "limit_to": 70
  },{
   "if": "road_class == SECONDARY",
   "limit_to": 90
  },{
   "if": "road_class == PRIMARY",
   "limit_to": 100
  }
 ],
 "priority": [
    {
   "if": "car$access == false",
   "multiply_by": 0.2
  },
  {
   "if": "road_class == CYCLEWAY || road_class == FOOTWAY || road_class == PEDESTRIAN || road_class == PATH",
   "multiply_by": 0
  },{
   "if": "road_class != TRUNK || road_class != MOTORWAY",
   "multiply_by": 0.8
  },{
   "if": "road_class == TERTIARY",
   "multiply_by": 0.7
  }]
}

Please note the condition with car$access, this allows the vehicle to drive oneway roads in reverse order but still gives a big penalty for these cases so that this only happens when necessary. Please note that this model can only act as a start and you should introduce a conditional for motorways so that the reverse direction is never used and probably many more.

Also with the branch text_value_rhs it is even easier:

{
 "speed": [
  {
   "if": "true",
   "limit_to": "car$average_speed"
  }
 ],
 "priority": [
    ... same as before ...
 ]
}

[scottclarke]

Thanks for replying.

Unfortunately, that doesn’t create routes using the private segments of road. I’ve tried adding
{
“if”: “access == PRIVATE”,
“multiply_by”: 1
}
to the custom model and adding a limit_to entry. I’ve also tried changing the graph.flag_encoders entry to car|block_private=false.

When I use the local MVT layer, the roads that are listen as private access in OSM do not have an overlay with any data - see picture for example. When I edit the map in JOSM and change the road segment to public access then re-build the application, the segment has an MVT entry. Is it possible that the private access roads are not passing/visible to the routing engine?

[karussell]

Did you use the roads encoder instead of car? Remove the line with graph.flag_encoders and do:

  ...
  profiles:
    - name: roads # or name it `car` or `emergency` or something
      vehicle: roads
      weighting: custom
      custom_model_file: empty # or directly use the custom_model above

[scottclarke]

Sorry I misunderstood.

The top custom model worked as I hoped when I changed “car$access” to “car_access”. Using “car$access” produced the following error message in NetBeans:
“Error: Cannot compile expression: in ‘priority’ entry, invalid expression “car$access == false”: ‘car$access’ not available”

Likewise, the second model produced the following error message:
“Operations limit_to expects a number but was “car$average_speed” (through reference chain: com.graphhopper.util.CustomModel[“speed”]->java.util.ArrayList[0])”

[karussell]

In order to use this new feature (“value expressions”) you need to compile graphhopper on the mentioned branch as it is not yet in a stable release:

@karussell

branch text_value_rhs