A green wave gives cyclists a stop-free trip

One tool that planners have to calm neighborhood streets and encourage bicycling is a “green wave.” Engineers set the traffic signals so they turn green just as a vehicle traveling at a certain speed arrives.

The basic premise of the green wave is to control the average speed on a segment of road. For example, if speeding is a problem in a corridor, the signals can be set for, say, 20 miles per hour. If drivers speed, they’ll only end up having to wait.

But green waves can also be set to benefit cyclists. That’s the case on Valencia Street in San Francisco, where the signals are set for 13 miles per hour, a very comfortable speed for most cyclists.

I had the opportunity to ride Valencia last summer when I was in San Francisco, and it was an almost religious experience.

The street has bike lanes, which give cyclists their own space, and saves them from feeling pressure to ride faster that motorists can sometimes bring. But riding along at a comfortable 13 mph, the signals turn green just as the leading edge of the wave gets there.

This happens again and again at every intersection. I felt like the hand of God was turning the signals green for me. That’s how amazing it is.

There may be streets in DC where this approach could work easily. I used to ride 11th Street from Columbia Heights into Downtown frequently. And on that street, the seemingly random nature of the signal timing meant frequent stops and starts, for both cyclists and motorists.

Of course, green waves are easier said than done. In a complex gridded city, perpendicular streets also have signal timing that needs to fit into a larger pattern. But in targeted corridors, a green wave can calm traffic and encourage cycling.