Evaluation of Adaptive Maximum Feature in Actuated Traffic Controller

Abstract

Several actuated traffic controllers contain the adaptive maximum feature, with which controllers can adjust the maximum green intervals for actuated phases within specified upper and lower limits according to fluctuating traffic demand. It has been difficult, however, to evaluate the merits of this and other features available in modern traffic controllers. Recent developments in traffic signal control system hardware and software technologies have now made it possible to evaluate controller features in a realistic and risk-free environment with hardware-in-the-loop simulation (HILS). HILS is a method of simulation in which one or more actual traffic signal controllers are physically linked with a microscopic traffic simulator. The performance of the adaptive maximum feature is demonstrated with HILS, which consists of an EPAC300 traffic controller and the VisSim microscopic simulation model. The demonstration was conducted at an isolated, fully actuated intersection in Richmond, Virginia. In a feasibility test, the HILS results indicated that the adaptive maximum feature was able to provide traffic signal control operations as efficiently as normal maximum green intervals optimized by Synchro. However, in a robustness test, where 15% changes in traffic volumes were considered, the adaptive maximum feature outperformed the normal settings for maximum green intervals.