Implementation of a Dynamic All-Red Extension at Signalized Intersections in North Carolina: Evaluation of Driver Adaptation and Operational Performance

Abstract

The dynamic all-red extension (DARE) system was designed to reduce crash risk from red light runners by protecting vehicles entering the intersection on the cross street from potential red light violators on the main-line approach. The safety system intervenes in the operation of a traffic signal when it senses that a vehicle is likely to violate the red indication of the main-line approach by holding the signal controller timing in the all-red clearance interval before switching the right of way and therefore allowing the offending vehicle time to clear the intersection before the next phase receives a green indication. North Carolina Department of Transportation has implemented DARE at nine traffic signals across the state since 2011. In Phase 1 of this project, yellow light running and red light running were used as measures of whether drivers adapted to the installed systems over 12 months, and the frequency and duration of red extensions over 3 years were used as a measure of system operation and performance. Results suggest that driver habituation to the system was minimal from before DARE installation to compliance data results 12 months after DARE installation. DARE operated successfully over a 3-year period and remains in operation with minimal surveillance at the study locations. The dynamic lengthening of the all-red interval was not associated with noticeable increases in delay at the rural and isolated study locations.