Green Wave: A series of traffic lights timed so they’re all green for traffic
travelling at the expected speed.
Green waves are an established concept in traffic planning. A series of traffic lights is timed so that once a vehicle passes the first light, if it’s travelling at the expected speed, then all the subsequent lights will be green as it passes them. The problem for cyclists, is they’re normally set for a speed of about 30 mph (50 kph). This is a bit too fast for the average cyclist. The obvious problem with this is that cyclists keep having to stop at red lights. This has the knock-on effect that a lot of cyclists end up jumping the red light, not very safe, and not very good PR for cyclists. A less obvious problem is that drivers of other vehicles want to get to the lights before they turn red, meaning a lot of unsafe overtaking of cyclists tends to happen.
Green waves timed for cyclists were first introduced into Copenhagen and Amsterdam in 2007, San Francisco also began implementing them in 2010. These schemes assume an average speed of between 16 and 20 kph (10 to 12 mph). What ends up happening is cyclists ride at the same speed, in a group. This makes them more visible to cars and dangerous overtaking is reduced.
The average speed of cyclists in Copenhagen before the green waves were introduced was found to be 16 kph. 20 kph was chosen to improve the traffic flow of cyclists by encouraging the majority to speed up a bit and the fastest to slow down. The green waves in Amsterdam work for cyclists
Melbourne has now introduced a green wave timed for cyclists. You can read more about it here.