Empirical delays from actuated and optimised static signal settings compared

Abstract

Many intersections have varying mechanism for vehicles right of way as they approach the intersection. With actuated signal, induction loops buried in the roadway stop-line, video, infrared or microwave detection system automatically adjusts timings relative to prevailing degree of saturation. An intersection without such detection system operates on fixed times (static). Signal settings are based on fixed proportional distribution of effective green per cycle time. In the paper, daylight and dry weather traffic performances at standalone signalised 4-way intersection were investigated under actuated and optimised signal timing conditions. Based on the hypotheses that peak traffic performance at standalone between optimised static and actuated signal settings are insignificant; discharge rates, delays and effective green timings for both were estimated compared and contrasted. Given that an optimised static signal assigns predetermined time irrespective of traffic demand; saturation flows were fixed at 1900 for straight, 1800 left turning and 1700 right turning vehicles per hour per lane respectively. Results show marginal differences in peak period effective green, discharge rates and delays. The paper concluded that optimised static signal can produce good results and should also be considered especially at standalone intersections where traffic operations are at peak regularly.