OSMTopology - GeoSmartCity-CIP/gsc-opentripplanner GitHub Wiki

The issue is connectivity between OSM ways, or the "topology" of the OSM data. Data that yields a good map for visual use is not necessarily usable for routing. It's not sufficient for ways to overlap or come near each other. They actually need to share a node for OTP to pass from one way to the other. This allows us to distinguish between bridges or flyovers and intersections.

Fortunately OSM is a user-editable dataset. You can just log in and start fixing the pedestrian bridges. This is one of the most common edits we need to do when deploying OTP for a new region.