Riding The Green Wave

Bike-friendly cities in Europe have retimed traffic lights in bike corridors to correlate with manpowered speeds instead of automobile speed limits. The practice is called “green wave.” A preliminary study conducted on San Francisco’s Valencia Street suggests that retiming lights for vehicles moving 12 mph—average bike speed—would make the road safer for everyone by reducing the number of bikers running red lights (when you catch every one, eventually you will run one) and reducing the likelihood of bike/car collisions.

And, though the speed limit on Valencia is (I believe), 25 mph for cars, the vehicles actually move at 8-20 mph according to the study. Green wave design would therefore reduce car travel times during peak traffic times, though it might slow them during off hours.

A green wave corridor might tempt bikers to take that route more frequently, easing bike-car frictions on other streets. But then again, unless green wave routes are abundant, their benefits may not outweigh their implementation costs (in the vicinity of half a million dollars)—or their potential to irritate frustrated drivers that much more.

What do you think? Is green wave design a good idea on high-use bike corridors?