An Exploration Of Modeling Of Right-Turn Lane Capacity At Signalized Intersection

China is a country where bicycles are commonly used in urban travel. There are no conflicts on the link of the roadways between bicycle traffic and vehicular traffic because a side median is used to separate these two flows. However, there are heavy conflicts between bicycle traffic and vehicular traffic at intersections. Due to the layout of carriageway for vehicles and bicycles, the right turn vehicles will conflict with through bicycles at intersections. The objective of this study is to explore the potential capacity of signalized intersection, especially the potential capacity of right turn movement at signalized intersections under mixed traffic condition. New concepts of bicycle group and grouping rate were introduced in this study. Relationships among bicycle volume, number of bicycle group, and grouping rate were found. The critical gaps and follow-up times of right turn movement traversing bicycle fleets were analyzed. The impact to the critical gaps and follow-up times of right turn vehicles made by the width of bicycle lane and lateral clearance of bicycle group were also analyzed. Thus, a bicycle-grouping based model was developed to estimate the potential capacity of right turn movement under the green indication. The model was calibrated using the collected data from eight signalized intersections of Beijing and proved robust after hypothetic test. This model is very useful for the estimation of capacity under mixed traffic conditions, which is a unique feature of transportation network in China.