Even with this additional capacity, the Brooklyn Bridge path gets a lot more cyclists and pedestrians than it can comfortably handle. Pedestrians complain bitterly about the cyclists, and vice versa. Often it is deserved: I've seen many thoughtless cyclists bombing down the offramp, and many clueless pedestrians drifting into the bike lane without looking. But mainly, the pie is too small for all the people who now want a slice. We need more capacity.
There have been proposals in the past to simply ban cyclists from the bridge, and the satirical @bikelobby account on Twitter has capitulated, but often the proposal is to build a new bikeway somewhere on top of the existing bridge structure, as with this 2012 proposal by City Council members Lander, Chin and Levin. I don't think we need to spend that much money; we should simply convert one of the current car lanes to a two-way cycle track.
Converting car lanes to cycle tracks is also not a new thing. It's been done over and over again by the city in the past seven years, first on Ninth Avenue, then Eighth and Kent and now even on the Pulaski Bridge, where the current multiuse path between Greenpoint and Long Island City is similarly strained. This would just be the same thing on the main level of the Brooklyn Bridge, and then the upper multiuse path could be dedicated to pedestrians. It's been proposed for the Brooklyn Bridge before, by Streetsblog commenters and Robert Sullivan.
You might think that the city could not afford to give up that car capacity, but in fact it might wind up increasing the total number of people who cross on the Brooklyn Bridge. There are no buses (or trucks) currently allowed on the bridge. The Manhattan Bridge bike path is well traveled, especially during rush hours, and the number of cyclists can rival the number of cars on nearby lanes.
Last month, at 7:30 on a Tuesday, Clarence Eckerson of Streetfilms took a quick count on the Manhattan Bridge. He counted a hundred cyclists in two minutes and 23 seconds, a rate that corresponds to
In a subsequent tweet, Clarence acknowledged that his sample may not have been representative. "well I am sure that pace didn't hold up!" he wrote. "A dozen were on a tour group" But even if the typical peak counts are not that high (see this PDF from the city DOT), they are probably higher than 476 per hour, and maybe higher than 1170 per hour. This suggests that one of the lanes on the Brooklyn Bridge's main deck would carry more people in the peak rush hour as a two-way cycle track than it currently does as a single car lane.
Clearly there is more research to be done: more samples of peak hour bike and motor vehicle traffic, on both the Brooklyn and Manhattan Bridges. I'm looking forward to the Streetfilm!