3 door articulated bus being tested in the Bronx
One of the problems with speeding up bus movement (yesterday, on my bicycle I beat a Metro Express bus on Georgia Avenue starting from around Kansas Avenue to 9th and H Street NW, and I stopped a bunch of times too) is disembarking (getting off of the bus).
In fact, Dr. Gridlock in the Post had a bit on this, when a reader wondered why people don't disembark from the rear of the bus to speed things up. I think we should move to such a system for speed reasons. This bus being tested in NYC, see "NYC Transit tests three-door bus in Bronx" from the New York Daily News, would be a way to make such a system more palatable, by offering two rear doors. (And would be a reason to use articulated buses instead of the double decker buses that I am normally a proponent of.)