In the last three years, New York City has built 200 miles of bike lanes. Daily ridership is up—some estimates say it has nearly doubled since 2005—after years of tepid growth.

During each morning rush, thousands of riders cross the four main East River bridges. Bikes crowd the Hudson River Greenway and are on the rise along First and Second Avenues, where the city has installed lanes protected from traffic by rows of parked cars. The city's streets now include 482 miles of lanes and a total of 1,800 miles are planned by...