Welcome to the Dilemma Zone. It sounds like a reality TV show, but it's actually something most drivers encounter every day: the moment when, approaching a yellow traffic light, you must decide to continue through the intersection at the same speed, hit the gas or apply the brakes. Each of these decisions carries risks. A sudden stop could result in a rear-end collision. A burst of acceleration could bring a ticket. Easing through the intersection makes you a T-bone target. Research indicates that only 1.4 percent of drivers cross the line once the light turns red -- but 20 percent of fatalities happen at intersections, according to the Federal Highway Administration. While most of us safely navigate intersections every day, it only takes one bad decision to put your car, life and insurance rates at risk.
So what is the Dilemma Zone?
Hesham Rakha, director of the Center for Sustainable Mobility at the Virginia Tech Transportation Institute, defines the Dilemma Zone as the place where a driver has no feasible choice. He can neither stop nor continue through the intersection before the light changes to red. The standard yellow time is 4.2 seconds on a 45 mph road. On faster roads, the length is longer. The formula is based on two assumptions: It takes the average driver one second to perceive and react to a yellow light and 3.2 seconds to safely stop the car. However, research released last fall found that 4.2 seconds is just not enough time in many situations. Rakha and fellow researchers determined that perceiving and reacting to a light change takes a bit longer than one second and deceleration times are much longer than standard yellow light times. Poor road conditions slow both reaction and stop times. Data showed that 43 percent of drivers who crossed the stop line during a yellow light were unable to clear the intersection.
A warning light for the caution light
A longer yellow light isn't necessarily the answer, Rakha says.