Derives the lane-occupancy key for a given route segment.
Roundabout "inside" segments share a single key per roundabout because
vehicles cross ring lanes during gradual merges, so per-ring-lane keys
would be inaccurate. Normal intersection "inside" segments return an
empty string (ignored by the occupancy tracker).
Derives the lane-occupancy key for a given route segment.
Roundabout
"inside"segments share a single key per roundabout because vehicles cross ring lanes during gradual merges, so per-ring-lane keys would be inaccurate. Normal intersection"inside"segments return an empty string (ignored by the occupancy tracker).