Estimation of uniform delay of permitted left turns from exclusive turn lanes

Abstract

The Highway Capacity Manual (HCM) defines uniform delay as a portion of control delay and estimates it based on the flow diagram originally developed for a protected movement. This paper demonstrates the shortcomings of the HCM delay model in the estimation of uniform delay of permitted left turns from an exclusive lane (PLTEL), and proposes a new uniform delay model developed for PLTEL. The control delays estimated by the original HCM model and the one estimated by the proposed uniform delay model for PLTEL were compared against those from corridor simulation. Results showed that the HCM model tended to underestimate uniform delay, and the proposed model for PLTEL showed improved results. © 2006 ASCE.