Traffic control in urban areas, a survey among road managers

In The Netherlands a large number of intersections in urban areas are controlled by traffic lights. Each traffic authority has an overview of the equipment under his jurisdiction but a countrywide overview was not available. From an exploration, it appeared that the number of intersections controlled by traffic lights was not known. It was also not known from which design viewpoint the different road authorities handled, nor what policy there was. The NHTV and DTVConsultants started in 1998 an inquiry by means of a written survey among the 569 traffic authorities with the objective to gather information about all the traffic control aspects in The Netherlands. The response rate was very high, about 540 (95%) responded. Almost all of the non-responders turned out not to be in charge of traffic control devices. From the findings and a preliminary simulation study, it may be concluded that, when compared, the delay on intersections is some factors bigger than the delay on motorways