Estimation Method of Saturation Flow Rate for Shared Left-Turn Lane at Signalized Intersection, Part II: Case Study

Abstract

This paper is a case study to estimate the Saturation Flow Rate (SFR) on a practical shared left-turn lane during peak hour and off-peak hour using KPSS test method and Highway Capacity Manual (HCM) method. The results declare that the value of SFR estimated by HCM is less than the one estimated by KPSS test method during all time periods. The difference is 4.1% during off-peak hour while 1.2% during peak hour. However, this slight discrepancy could cause remarkable difference in cycle length and average vehicle delay. For example, compared with KPSS test method, in off-peak hour the cycle length increases by 19.2% while the average vehicle delay increases by 14.0% when using HCM method.