Optimization of signal timing for improving traffic flow on a highway segment using TRANSYT7F

Using optimisation tools to improve the vehicular traffic performance within a road network has been studied extensively. This study examined the capabilities of a modelling software TRANSYT7F (T7F) to modify the input parameters to STREAMS, which is a system that controls the signalised intersections in Toowoomba, Queensland. Traffic flow on the Warrego highway segment, passing through nine signalised intersections from Anzac Avenue to Mackenzie Street, has been chosen in this study. A set of traffic flow scenarios accommodating a range of parameters including highway geometry, traffic volumes, and corresponding traffic actuated control settings were used in this modelling and optimisation. The Genetic Algorithm within T7F was adopted to identify optimum solutions using disutility index and performance index to examine the efficiency of the present timing arrangements. Results revealed T7F could be used to refine input parameters to improve performance of the highway segment further and hence making a set of more optimal allocation of green times possible. Considerable improvements have been noticed from comparing the control delay, number of stops, fuel saving and travel time on this highway segment. Despite these results, the actual traffic conditions are much more complicated it is advised to utilise more desktop studies to investigate the real operational scenarios.