ATLANTA, Sept. 20 (UPI) — Aggressive drivers and those who drive too timidly are both causes of major traffic jams, U.S. researchers say.
While the immediate cause of a jam might be an accident or construction or drivers changing lanes on busy roads, it is how the drivers react in the cars behind that causes traffic to slow to a halt, Britain’s The Daily Telegraph reported.
Researches at the Georgia Institute of Technology say aggressive motorists who drive too fast and too close to the vehicle in front, or timid motorists who leave too big a gap, create a “wave of deceleration” backwards down the road until traffic grinds to a stop.
Jorge Laval at Georgia Tech found that when drivers changed their speed, they caused drivers further back to change theirs, and the change in speed passes like a wave backwards through the traffic.
Eddie Wilson, an expert on traffic modeling at Britain’s Bristol University, said: “The exact point at which a traffic jam starts is very difficult to measure as it often causes a wave that produces a jam 20 miles farther back.”
Timid drivers had the biggest impact because they “shied away” when the car in front started slowing down, and deliberately started driving even more slowly to increase the gap between them, researchers said.
Aggressive drivers also caused speed to drop because they braked hard at the last moment to avoid driving into the car in front, researchers said. They then had to drive more slowly to open up a space again.
Copyright 2010 United Press International, Inc. (UPI). Any reproduction, republication, redistribution and/or modification of any UPI content is expressly prohibited without UPI’s prior written consent.