At a traffic signal installation the traffic signal controller relies on the information provided by the vehicle detection system to control green settings and intergreen periods between phase changes. The efficiency of the installation can only be as good as the data provided by the detection system. Existing vehicle detection systems are almost exclusively based on inductive loops installed below the road surface on the approaches to a junction. Loops are expensive to install and maintain, also, because of their situation in the road they are frequently made unserviceable by road surface movement or statutory undertakers carrying out maintenance on their equipment. A study, carried out by the authors under contract to the department of transport, has investigated and reported on the feasibility of providing reliable information to the traffic signal controller using different forms of above-ground detection techniques and stand-alone sensors situated in the road surface. The major problem of communicating information from the sensors to the controller unit has been examined and potential solutions are identified. A number of detector systems utilizing different combinations and layouts of sensors have been proposed and investigated, and the future of vehicle detection systems to the end of this century is assessed. (a) for the covering abstract of the seminar see IRRD 273510.
Abstract