Investigation on Two-Stop-Line Signalized Roundabout: Capacity and Optimal Cycle Length

Abstract

Two-stop-line signalized roundabouts (TSLSR) are widely utilized in China. To calculate the capacity and optimal cycle length accurately, a model considering internal space constraint of the roundabout is developed in this paper. Firstly, the operational principle of TSLSR is analyzed. TSLSR is modeled as being equivalent to a four-phase intersection with left-turn protection phases, and the left-turn lane is further simplified as the “short-lane model”. Secondly, based on the above analysis, the capacity of TSLSR is modeled and additionally, the accuracy and sensitivity of the model are also analyzed. Finally, the optimal cycle length of TSLSR which maximizes the capacity is put forward. Results show that the accuracy of the capacity model is low without considering the internal space constraint of the roundabout. However, the model developed in this paper is shown to improve the accuracy (about 20%) and control the relative error to be within 10%. The parameter sensitivity analysis demonstrates that the cycle length and radius of the central island have a significant influence on the capacity of the left-turn lane and results in an optimal value of signal cycle length maximizing the capacity.

Study of Full Controlled Green Time Roundabouts – An Intelligent Approach

“…Concerning signal timing studies, several researchers tried to enhance roundabout capacity by applying a signal timing plan and adjusting the phase sequence [24][25][26][27][28][29][30]. In [24,25], direct and full control method was tested and a two-stop line roundabout was proposed to help left-turning vehicles.…”

“…Concerning signal timing studies, several researchers tried to enhance roundabout capacity by applying a signal timing plan and adjusting the phase sequence [24][25][26][27][28][29][30]. In [24,25], direct and full control method was tested and a two-stop line roundabout was proposed to help left-turning vehicles. The research calculated the best green time for straight traffic on each approach at the first stop line and vehicles turning left on the circulating lanes at the second stop line [25].…”

“…In [24,25], direct and full control method was tested and a two-stop line roundabout was proposed to help left-turning vehicles. The research calculated the best green time for straight traffic on each approach at the first stop line and vehicles turning left on the circulating lanes at the second stop line [25]. From the research, it can be found that cycle length and island size could affect the flow of left-turning vehicles on the circulating lanes.…”

Evaluating The Effects of Signal Control Applications on Roundabout’s LOS Performance Using VISSIM Microsimulation Model

“…The study findings suggested that cycle length between 60s and 90s is suitable for a 2-lane roundabout that uses the TSLSR phasing plan method. In addition, Jiang et al (2019) [12] found that the cycle length and radius of the central island affected the capacity of signalised roundabout using the TSLSR phasing plan. Thus, the selection of optimum cycle time for TSLSR should be carefully examined to avoid undesired results.…”

Sinyalize Dönel Kavşaklarda Diferansiyel Gelişim Algoritması ile Sinyal Süre Optimizasyonu

“…Jiang ve diğ., yapmış oldukları çalışmada, sinyalize dönel kavşağın kapasitesini maksimize eden en uygun devre süresini belirlemeyi amaçlamışlardır. Sonuç olarak, çalışma kapsamında geliştirilen model ile kavşak kapasitesinin önemli oranda arttırılabileceği görülmüştür [18].…”