LEDs
June 8, 2006
Source from: http://en.wikipedia.org/wiki/Bicycle_lighting#LEDs_2
In many countries LED flashers are the norm for rear lights. In others such as Germany flashing lights are forbidden by law. In the UK flashing LEDs (front and rear) are legal from October 2005. It has been found that people tend to underestimate the distance to blinking lights and also that drunken drivers are attracted by them, and there is evidence that they are harder to place than a steady light; on the other hand they have also been shown to be between three and five times as visible as a steady light of equivalent brightness. Most LED lights will work in either flashing or steady modes; some have multiple banks of LEDs allowing both at once. The answer is to have one of each, or a light which will do both simultaneously.
The most common power source for rear LEDs is a set of alkaline cells; rechargeable cells are less environmentally damaging but have a much shorter run time. In both cases the battery tends to fail quickly when it goes; it is widely considered good practice to have two rear lights in case a battery fails en route.
