[bsder]

The real issue is that the BACK bus needs to pass the front bus and move ahead a couple of stops.

Pittsburgh, however, as an unusual misfeature in that the single bus lane goes the wrong way against one way traffic (3 lanes of cars going one way--1 lane of bus going the opposite) for a non-trivial amount of length flagged as "hotspots".

This means that while automobile drivers using the bus lane is a self-correcting problem, a bus cannot pass another bus in those areas.

(I call the wrong way bus lane a "misfeature" because it regularly results in out-of-towners winding up dead because they didn't look both directions on a "one way" street. This is particularly tragic when the out-of-towner is someone who is visiting Children's Hospital because their child is being treated for some very aggressive disease.)