Before we only worked on subsequent quick turns, as in:
`right, right` keeps the user on the rightmost lanes.
This changeset modifies the logic to work on any subsequent steps
that are "quick" and have lane information we can constrain later.
Because we do not have a from-lane => to-lanes mapping we take the
lanes left and right of the turn lanes into account when heuristically
assigning the leftmost / rightmost lanes.
There are some edge cases where this still does not give us the optimal
solution but it gets close to what is actually possible at the moment
without having a lane mapping in post-processing.
References:
- https://github.com/Project-OSRM/osrm-backend/issues/2625
fix rebase
This changeset implements Lane Anticipation on roundabouts, delimited
by enter / leave step pairs. It does not handle lane anticipation
within a roundabout.
Lane anticipation happens on the granularity of a valid roundbaout:
We discard partial roundabout (enter without exit or exit without
enter) or data issues (no roundabout, exit before enter).
Related:
- https://github.com/Project-OSRM/osrm-backend/issues/2626 for lanes
within a roundabout
- https://github.com/Project-OSRM/osrm-backend/issues/2625 for handling
going straight in lane anticipation
