Preserve boarding costs by direction?

[kuanb]

Right now peartree is crude in that it assumes/averages the boarding cost for a specific line for both directions that it serves. This is not ideal, as it poorly represents service that is unbalanced (service that has lots of trips going in one direction and less in the other, for example).

[yiyange]

In addition to this, boarding cost of a given stop id is also averaged over different routes (of the same operator) and different shapes (shape_id - unique set of stop sequences). It is biased in cases where, for example, at Stop A, there are two routes going different places with route X having frequent services (small headway) whereas route Y having infrequent services (large headway). But regardless where the destination is, the boarding cost is the same and it is underestimated for route Y but overestimated for X.