Abstract
''Transyt'' is a computer program which automatically finds the best settings to use in a network of fixed time signals. The program consists of a traffic model in which total delay is minimised by a hill-climbing strategy. In the model, allowance is made for flow interaction between road sections, control by signals or a priority rule and platoon dispersion. Networks of up to fifty intersections in any configuration can be solved. The hill-climbing strategy optimizes phase duration and offsets. A new form of time-distance diagram is given. The ''Transit'' method has been tested by an experiment in West London. A thirty per cent reduction in delay was achieved and the model predictions were shown to be accurate.