Merging gap acceptance at midblock u-turn facility (a case study on multilane divided highway in Malaysia)

Abstract

A midblock U-turn facility is often provided on multilane divided highway to manage direct right turn maneuvers from main stream. Mid block U-turn facility provides a safe turn for drivers who want to change their directions. As the number of vehicles in major road increase, the driver who wants to do U-turn faces more difficulties to find a suitable gap. This study is conducted to find a critical gap acceptance and empirical relationship between U-turning delay and volume on near-side traffic lane at midblock U-turn facility in multilane divided highway. Methodology of the study was observation and in order to have a precise data, video recording technique was used. Greenshields gap acceptance method was used to analyse the data. Through the collected data, a total of 916 rejected gaps and 810 accepted gaps were used for analyzing and results show that critical gap acceptance is 3.5 sec. Meanwhile, there is an empirical relationship between delay of U-turning and volume on nearside traffic lane on major road.