Abstract
Objectives for the evaluation of traffic lights as seen by the drivers such as waiting time, travel time, average speed, are discussed and compared with those of coordinated traffic lights. Measured values for average speed and travel time show a great variation, even in off-peak hours. Great differences were observed between the actual number of vehicle stops in a coordinated series of traffic lights and the theoretical number. Objectives as seen by the road authorities and from an economic point of view are also discussed. A number of problems still to be solved are posed.