Tuesday, April 12, 2011

Mass transit and bridges

New York bridge capacities

Streetsblog ran the above image in an article yesterday, mostly focused on the Brooklyn Bridge. It shows that bridges in New York City carried the most people back in the days when subways and streetcars used them more heavily. There are a few caveats for the image—for instance, the Manhattan Bridge was partially closed in 1989, so that affects its numbers. The diagram also leaves out the fact that some of the rails were moved into tunnels under New York-area waterways. However, there was an overall loss in the number of rail links into Manhattan.

To me, this underscores the value of making a "whole count" of traffic on a street or bridge. As a former University of Minnesota student, it also makes me think of the double-decked Washington Avenue Bridge, the most multi-modal bridge in the Twin Cities. Mn/DOT and other traffic agencies focus on automotive traffic, and have neglected to count pedestrians, cyclists, and transit riders. What is the overall traffic on Washington Avenue? I wish I knew. That bridge carried 28,000 vehicles per day on the lower deck, but the only number I've found giving an indication for the upper deck is 5,000 people at the peak hour—a rather useless measure for me, and I'm not sure if that's exclusively the upper deck or if it's meant to be for the entire bridge.

Right now, the Washington Avenue Bridge is being partially disassembled to make way for light-rail construction—half of the lower bridge deck is currently removed. The Central Corridor line will take away two traffic lanes, and will even eliminate private car traffic entirely along a stretch of Washington Avenue (the road) on campus, but it could very well have the effect of increasing the total number of people crossing the bridge each day.


  1. The City's 2010 Count Report estimates total travelers over the Washington Ave Bridge as 71,400, of which 9.6% are bikes, 19.9% peds, 32.7% transit, and 37.6% motor vehicle occupants. I just came across it now so I'm not sure of their methodology - here is the link to their counts page: