Lane-level routing (experimental)

A route that says which lane to be in, not only which road. It runs on a GMNS database:

duckosm gmns monaco.duckdb
duckosm lane-graph monaco_gmns.duckdb       # 3,182 lanes, 3,890 turn + 834 lane-change links
duckosm route-lanes monaco_gmns.duckdb <from> <to> -o route.geojson

route: 115 lanes, cost 3876, maneuvers: right turn, right turn, merge, fork, lane change, … (25 in all), right turn, U-turn

<from> and <to> are lane ids (<edge_id>_<lane number>, e.g. 4737533508550016661_1), or edge_ids (then their lane 1). An unknown id gives "no lane route", as an unreachable lane does. The lane graph links each lane to the lanes it can turn into (legal turns only) and to the lanes beside it (a lane change). The cost is metres, plus a penalty for each turn and lane change. lane-graph saves the graph in the GMNS database (lane_driving.lane_edges) so that repeated routes are faster; route-lanes also works without it. Needs pip install "duckosm[routing]".

from duckosm import build_lane_graph, route_lanes
build_lane_graph("monaco_gmns.duckdb")
r = route_lanes("monaco_gmns.duckdb", from_lane, to_lane)
r["lanes"], r["cost"], r["maneuvers"], r["geometry"]

Limits: where OSM has no turn:lanes (most roads), any lane may take any legal turn, so a route can turn from a lane a real driver would leave first. Good for planning, not for lane-accurate control. Driving by default; -m cycling runs too, but cycling roads mostly have one lane.