Connecting SCOOT to CORSIM: real-time signal optimization simulation

Adaptive signal control systems react to traffic in real-time and adjust the signal timings to improve signal efficiency. SCOOT is the most widely implemented system. It comes from the UK with over 200 installations worldwide including the US. Average delay reductions of 20 percent have been shown in urban networks that employ adaptive signal control systems. However, these benefits vary between cities. Until now, no commercially available adaptive signal control system could be modeled across a city-specific network prior to installation. The University of Utah has developed a simulation modeling connection between the Federal Highway's CORSIM model and the SCOOT adaptive control system. SCOOT runs on the VMS operating system, CORSIM on Windows NT. The two are connected via Ethernet with a dynamic link library interface that extracts the signal state and detector information from CORSIM and converts it to a format that SCOOT understands. SCOOT processes the information and sends it back across the Ethernet. In a completed loop, the optimized signal timing is then communicated from SCOOT to CORSIM, which implements the timing and updates the traffic simulation. This work offers traffic engineers the opportunity to evaluate the impact of SCOOT in a simulated environment prior to installation of the system. This paper reports the findings of the simulation of an actual urban network.