[jmecklenborg]

Dedicated lanes won't work because dedicated lanes are easiest and cheapest to establish where they are least-beneficial. They are most-needed at the busiest city intersections, but nobody's ever going to agree to wall off a 4-way intersection to give buses a fully-protected at-grade path (this is what third-world BRT systems do that the Tea Party loved so much). Building underpasses or overpasses at intersections just for buses moves at-grade stops well-away from corners and convenient transfer points. Building an underground station just for buses at a transfer point is theoretically possible but horrendously expensive - certainly more than $50 million per example.

Additionally, BRT signal priority doesn't really work because a)things get screwed up during gridlock and b)politicians can turn off the signal priority. This actually happened in Cleveland.