Comparison of Observed and Estimated Shared Left-Turn Lane Capacity at Signalized Intersections.

Document Type : Research Studies

Author

Civil Engineering Department., Faculty of Engineering., El- Mansoura University., Mansoura., Egypt.

Abstract

Turning movements at signal-controlled intersections considerably affect the approaches' capacities. Capacity of shared left-turn lane (i.e where straight-ahead and left-turning vehicles share the same lane width) with opposing flow is greatly influenced by a number of traffic and geometric parameters at signal-controlled junctions. This is particularly important for normal two-phase controlled intersection where all left-turners (or right-turners in U.K.) have to face conflict with the opposing flow since both of them have to share the same green phase. 
Different models have been developed recently for capacity calculation of shared left-turn lanes. These models are based on diversity of assumptions and each has some limitations when applied in practice. The main objective of this paper is to check these models and compare their results with capacities obtained from field observations. At last, conclusions regarding their accuracy and to what extent they can represent the actual capacity of shared left-turn lanes are presented. 

Main Subjects