Computer-controlled road-traffic signal systems in the United Kingdom

The paper is concerned with dynamic control, and, in particular, traffic-signalling systems that use computers as the controlling element. In the UK, such systems have two principal applications: the first deals with traffic problems in cities and towns, and the other applies to motorways. Area traffic control is the name given to those systems that apply to cities and towns, and traffic control for motorways is provided for by the motorway communication system. These systems have evolved at different times and for different reasons, and are fundamentally different in their operation, and so are dealt with separately. The history of traffic control, the development of computer-controlled traffic-signalling systems and their subsequent implementation are described, as are types of detector now in use and current research projects.