Quantitative Evaluation of Fully Actuated versus Nonactuated Coordinated Phases

Abstract

Intersections on coordinated arterials typically run in a semiactuated mode, where the end of green for the coordinated phases is fixed in time. During cycles when demand for the coordinated phases is low, the intersection tends to become idle while vehicles wait on minor movements. Actuating a portion at the end of the coordinated phase enables the controller to allocate the green time in response to demand for the coordinated movement. Green time is reallocated to other phases when demand for the coordinated movement is low but is retained by the coordinated movement when demand is high. The operational impacts of actuating the last 9.6 to 11.6 s of the coordinated phases (10% of cycle) at an actuated intersection are investigated by using cycle-by-cycle calculations of measures of effectiveness. The use of fully actuated instead of nonactuated coordinated phases can better balance volume-to-capacity ratios and decrease split failures for minor street movements without major impacts on progression through the coordinated movements. It is recommended that agencies consider actuating coordinated phases to provide robust control that more effectively responds to changing traffic conditions.