Effect of supplemental signal on start-up lost time at signalized intersection

Abstract

Supplemental signals have been widely used at intersections to reduce the impact of heavy vehicles. This study aims to measure the effects of supplemental signals on Start-Up Lost Time (SULT). A corrected method of calculating SULT considering heavy vehicles are presented. The method also introduce into basic saturation headways, locations of the heavy vehicles and the four types of headways. Field studies were implemented at 18 approaches of 6 intersections in Nanjing, China. The results show that the existence of heavy vehicles has significant influence on both of headways and SULT at signalized intersection. Supplemental signal is effective countermeasure to reduce the influence of heavy vehicles. The study will be helpful when measuring SULT at intersection with supplemental signal.