Abstract
Traffic lights tend to reduce the number of conflict points and therefore the number of potential conflicts at intersections. Their safety effect is paramount in the case of high traffic densities over the day. The presence of traffic lights seems to have a more positive effect on the safety of car drivers and their passengers then on that of cyclist and moped riders. It also seems to reduce the number of flank collisions. The proportion of rear end shunts will increase of the reduction of the other accident types. Traffic lights should be kept working overnight with a special programme to reduce waiting times to a minimum.