Empirical investigation of the effect of countdown pedestrian signals on driver behavior and capacity at urban signalized intersections

Improving pedestrian safety at urban signalized intersections is a continuing challenge for traffic engineers. The Light Emitting Diode (LED) countdown pedestrian signal (CPS) is a supplementary safety device that displays a countdown of the seconds remaining in the protected pedestrian-crossing phase at signalized intersections. This study investigates how CPS installed at signalized intersection affects the intersection driver behavior and capacity. A before-and-after study compares study variables and behavior of drivers at four signalized intersections in Washington, D.C.---when equipped with CPSs versus with traditional incandescent pedestrian signals. Study variables include vehicles 1) entering the intersection during the yellow phase; 2) stopping during the yellow phase; 3) stopping during the red phase; 4) entering the intersection between the yellow and red phases; 5) entering the intersection during the red phase; and 6) the headway. Standard statistical t and Z-tests were used to compare the difference in traffic characteristics between the traditional pedestrian signals and countdown pedestrian signals.;It was found that the CPSs had a statistically significant impact on driver behavior and intersection capacity.;Results of a driver behavior survey conducted for this study indicate that 63% of respondents agree that information provided by CPS improves driving decisions; 74% responded that countdown signal information positively affects behavior; and 83% indicate the countdown signal information affects braking or stopping maneuvers at signalized intersections.