An evaluation of SCATS Master Isolated control

Abstract

The well-known SCATS wide-area traffic control system has a unique feature for the control of a single non-coordinated signalised intersection known as SCATS Master Isolated control. The effectiveness of this control was evaluated using microsimulation and field surveys. Various SCATS-like adaptive control algorithms were developed and tested through extensive simulation tests with a wide range of demand flow patterns and a large number of control parameter combinations. Traditional vehicle-actuated and fixed-time control were also evaluated. The results for an algorithm that emulated the SCATS Master Isolated control, and the traditional vehicle-actuated control method are presented in this paper. A new survey method was developed, trialed and used for field surveys. The survey method produced a large number of timing, capacity and performance statistics. The surveys produced results that were in line with the results of simulation studies. The overall conclusion was that SCATS Master Isolated control gives better intersection performance than traditional actuated signal control as indicated by lower delays and shorter queue lengths achieved with shorter cycle times. Evaluation of the effects of detector failure indicated substantial benefits from the SCATS Master Isolated control in terms of all performance measures considered.