Effect of an Upstream Traffic Signal on the Capacity of a Downstream Two-Way Stop-Controlled Intersection

Abstract

This paper investigates the platoon dispersion model that is part of the Highway Capacity Manual 2010 (HCM 2010) and is used to forecast downstream traffic flows for analyzing both signalized and two-way stop-controlled (TWSC) intersections. The paper focuses on the effect of platoon dispersion on proportion of time blocked, conflicting flow rate, and capacity flow rate for the major street left-turn movement at a TWSC intersection. Existing HCM 2010 methodology shows little effect on conflicting flow or capacity for various distances downstream from the signalized intersection. Two methods are suggested for computing the conflicting flow and capacity of minor stream movements at a TWSC intersection that have more desirable properties than the existing HCM method. Further, if the existing HCM 2010 method is retained, results suggest that the upstream signals model be dropped from the HCM method for TWSC intersections.