The Road Traffic Authority is presently implementing a system for co-ordinating traffic signals throughout the Melbourne Metropolitan Area in Victoria. The system is known as SCRAM (Signal Co-ordination of Regional Areas in Melbourne). The aim of the Program is to provide traffic signal co-ordination for all primary and secondary arterial routes within Melbourne and to achieve improved operation and safety for all vehicles, public transport and pedestrians.SCRAM is based on the SCAT (Sydney Co-ordinated Adaptive Traffic) System which was initially produced in New South Wales. SCATS is now used in most Australian States and also in New Zealand. A total of 2300 traffic signals are presently operated by SCAT Systems.A survey to compare vehicle and travel characteristics under Isolated and Dynamic Signal Linking modes was conducted on a 13.5 km section of the Maroondah Highway in Melbourne during 1982. The survey used instrumented vehicles to ascertain route operational comparisons together with an intersection delay survey to ascertain effects on side-road traffic. The results of the survey were analysed during 1982/83 and they indicated that the Dynamic Linking mode of operation provided significant benefits for journey time, stops, delay and fuel consumption.The results of the field surveys were used to undertake an economic analysis of the SCRAM Program over a 10 year period. The co- ordination of the 1800 traffic signal sites in Metropolitan Melbourne is expected to achieve a net benefit cost ratio of 25.