The city of Groningen has installed a new device at traffic lights which gives extra green light time for cyclists when it rains.Long waiting times at traffic lights are a recurring source of irritation for many cyclists, and Groningen has invested a lot over the past few years in making its traffic lights more cycle friendly. Examples include green waves for cyclists at intersections and two green phases for cyclists during one light sequence. Despite these improvements, waiting times in bad weather conditions can still be long. For this reason Groningen and other Dutch cities have now introduced a rain sensor which ensures that cyclists get a green light more often when it rains.The optical rain sensor, which emits infrared signals, is the size of a hand and shaped like a horseshoe. The instrument is heated in order to be able to detect snow as well as rain. When precipitation interrupts the infrared signal, this is detected and a message is sent to a device that turns the traffic light for cyclists to green. The sensitivity (the delay signal) is adjustable. Currently, two types of optical rain sensors are on the market: the first registers rain and snow, while the second distinguishes four levels of precipitation, ranging from drizzle to heavy rain.A rain sensor can only be applied to modern devices. It cannot be used with traffic lights which are part of a network because influencing one traffic light would impact on a whole chain of traffic lights, which would undermine the set regulations for that particular network.It is already clear that the rain sensor is extremely effective at intersections with a large number of cyclists. This is why Groningen decided to install it at the intersection near the Oosterbrug. Because the sensor gives more green light time to cyclists when it rains, other traffic modes, including cars, buses and emergency services, have to wait longer at a time when the pressure on traffic is already greater due to poor weather conditions. In order to avoid excessive waiting times for other road users, Groningen has introduced a maximum traffic light cycle of 120 seconds (previously it was 90 seconds). Cyclists therefore no longer receive extra priority.Source: CHAMP Newsletter