Traffic signals in urban areas are often coordinated together on 'fixed time' plans that are pre-set to suit average conditions. SCOOT (Split, Cycle and Offset Optimisation Techniques) ia a new method of coordination that adjusts the signal timings in frequent, small increments to match the latest traffic situation. Scoot is designed for general application within computerised urban traffic control systems. The research and development of SCOOT has been carried out by TRRL. SCOOT systems have been implemented in Glasgow and Conventry and traffic surveys have been conducted by TRRL on a total of 62 signals. It is concluded that SCOOT reduces vehicle delay by an average of about 12 percent compared with up-to-date optimised fixed time plans; further substantial benefits are likely where, as is often the case, the fixed time plans are based on old traffic data