Analysis of Driver Behavior in Dilemma Zones at Signalized Intersections

Document Type

Journal Article

Publication Date


Subject Area

operations - traffic, infrastructure - vehicle, ridership - drivers, ridership - behaviour, mode - bus, mode - bike


Yellow interval (Traffic signal cycle), Video cameras, Truck drivers, Speed, Signalized intersections, Signalised intersections, Red light running, Motor vehicle operators, Madison (Wisconsin), Human behavior, Heavy vehicles, Drivers, Dilemma zone, Deceleration rates, Deceleration, Camcorders, Bus operators, Bus drivers, Braking, Behaviour, Behavior, Automobiles, Automobile drivers, Amber phase


A field study evaluated the stopping characteristics of vehicles 2.5 to 5.5 s upstream of signalized intersections at the start of a yellow interval, a region typically considered drivers’ indecision zone or dilemma zone. Characteristics included brake-response times for first-to-stop vehicles, deceleration rates for first-to-stop vehicles, distinguishing characteristics and prediction of first-to-stop versus last-to-go events, and distinguishing characteristics and prediction of red-light-running events. Consumer-grade video cameras temporarily installed at four high-speed and two low-speed intersections in the Madison, Wisconsin, area recorded dilemma zone vehicles. Several factors were measured for each last-to-go (n = 435) and first-to-stop (n = 463) vehicle in each lane during each yellow interval, including approach speed; distance upstream at start of yellow; brake-response time; deceleration rate; vehicle type; headway; tailway; action of vehicles in adjacent lanes; presence of side-street vehicles, pedestrians, bicycles, or opposing vehicles waiting to turn left; flow rate; length of yellow interval; and cycle length. The observed 15th, 50th, and 85th percentile brake-response times for first-to-stop vehicles were 0.7, 1.0, and 1.6 s, respectively; their observed deceleration rates were 7.2, 9.9, and 12.9 ft/s², respectively. Vehicles were more likely to go through than to stop under the following conditions: shorter estimated travel time to intersection at start of yellow; longer yellow interval; the subject was a heavy vehicle (truck, bus, recreational vehicle); absence of side-street vehicles, bicycles, pedestrians, and opposing left-turn vehicles; and presence of vehicles in adjacent lanes that went through. Heavy vehicles were more likely than passenger vehicles to run a red light. Vehicles were more likely to run a red light when vehicles in adjacent lanes that also went through were present and when side-street vehicles, bicycles, pedestrians, and opposing left-turn vehicles were absent.