Dynamic dilemma zone based on driver behavior and car-following model at highway–rail intersections

Abstract

This study introduces the concept of a “dynamic dilemma zone” (DDZ) road segment. A DDZ as opposed to a static dilemma zone is a road segment on approach to an intersection which varies in length based on fluctuations in vehicle speeds and the number of vehicles within a road segment. This is in contrast to a static dilemma zone which is based on a constant approach speed and a single vehicle in the road segment. The “dilemma” refers to the interaction of vehicle kinematics and perception–reaction time, where a vehicle could not clear the ‘intersection’ or stop before entering it. Car-following theory is used within the DDZ approach to model driver–vehicle behavior in platoons. It is found that the values of gate delay and gate interval times in car-following situations are greater than those with a single vehicle approach. The determination of the DDZ aids in defining the conditions which contribute to the likelihood of vehicle clearance (or stopping) at four quadrant gate highway–rail intersections.