Count the blocks until the next turn

Nobody has claimed this yet.

In dense, urban areas, it’s difficult for a driver to make sense of an instruction to “turn left in a quarter mile”. Instead, the user would benefit from an instruction to “turn left in 3 blocks”, such that there are two intervening cross streets. Along these lines, it would be nice to say “take the second exit on the right”, especially when exit numbers aren’t posted and freeway exits are close enough together that the instruction would otherwise be ambiguous.

This feature would require the `intersections` array in the route step. It may require some changes in OSRM Text Instructions, to the extent that we put anything distance-based in that library.

/cc @MoKob @bsudekum

Start by tracing how the route step's intersections array is exposed in the iOS navigation flow, then review the scope of OSRM Text Instructions for distance-based wording. Define how block counts and exit ordinals should be derived and presented, including cases where exits are unnumbered. Done means dense urban turns can use block counts and freeway exits can use ordinal instructions without ambiguity.

Written by the indexing model from the issue text.