Capacity of Urban Arterial Weaving Sections under Lane Signal Control Strategy

Abstract

An urban arterial weaving section has been considered a bottleneck in urban roadway systems, which is one of the key contributing factors to the occurrence of the capacity-drop phenomenon. This paper proposes a novel lane signal control method to regulate the weaving traffic flow at urban arterial weaving sections. With consideration of the operational characteristics of the weaving section and the imbalance of traffic at each entrance lane, a reduction coefficient of the weaving traffic was adopted. A capacity calculation model for weaving traffic under lane signal control was developed. The optimization model was established to derive the optimal lane signal control scheme. The objective function was to maximize the weaving section’s capacity, and the constraints were the safe time headway between two adjacent phases. The proposed capacity estimation model was validated using field data collected at a representative urban arterial weaving section in Chongqing City, China; it was found that the mean absolute percent error was 4.7%. Modeling results demonstrate that the actual capacity of the weaving section significantly increased after adopting the lane signal control strategy. During the morning peak period, the actual capacity was 3,265 pcph (passenger cars per hour), which improves by 28.14% under the optimal scheme of two-phase lane signal control. The weaving capacity improvement for the three-phase lane single control is found to be 3,458 pcph, which improves by 35.71% under the three-phase control strategy. This paper used capacity reduction as index to test the robust of entrance lane, facing the increasing demand for traffic.