4. Berkeley, Calif.
Number of bicycle commuters: 4,404
Bicycle commuters' share of overall population: 8.9%
Berkeley really loves its bicyclists and has done everything short of extending its middle finger toward area drivers to get the message across.
Berkeley was one of the first cities in the U.S. to block and divert traffic away from local streets and toward major arteries to create low-speed "bicycle boulevards" for riders to use as alternatives to congested high-speed thoroughfares. The combination of bike lanes, low speed limits and access to full roads puts bikes on par with cars on these streets and has the added effect of discouraging automobiles.
Portland and Eugene, Ore., and Madison have similar features, but Berkeley augments its boulevards with numerous bicycle routes, the Ohlone Greenway, a portion of the 300-mile San Francisco Bay Trail and the $6.5 million Berkeley Interstate 80 bridge that connects the city to the trail, East Shore State Park and the Berkeley Marina. The University of California at Berkeley certainly plays a role in cycling's success here, but credit the city at large with making its roadways so bike friendly.