Philadelphia An SUV growls inches from the rear bumper, and brake lights and headlights surround you. The air conditioner pumps cool air. Still, the temperature rises.
You simmer. You steam. And more and more often, say law-enforcement officials and authorities on driving habits, you boil over into road rage.
"It's the age of rage," said Leon James of the University of Hawaii, who has written several books on the issue of aggressive driving.
The National Highway Traffic Safety Administration says aggressive behavior is a factor in nearly 28,000 roadway deaths a year.
In a recent survey of about 520 motorists by the Automobile Association of America, almost 90 percent said they had experienced road rage during the last 12 months.
Sixty percent admitted to such acts as tailgating aggressively, flashing headlights, gesturing obscenely, deliberating obstructing the road and verbally abusing fellow drivers.
One percent said they had been physically assaulted by other motorists.
Alejandra Soto of the Insurance Information Institute in New York said men ages 20 to 40 were most likely to drive aggressively.
"We've found that men who are involved in a road rage incident are likely to repeat the offense if not caught," she said.
It is typical to find conflicting views of road ragers, James said. "You can have a person who is quite calm in most other facets of their lives, but once they get behind the wheel, watch out," he said.
That's mostly because there are too many drivers on too few roads, said Elizabeth Baker of the National Highway Traffic Safety Administration.
"Roadway congestion is considered the number one factor which tends to exacerbate aggressive driving behaviors," she said.
"Basically the number of cars has overloaded the system. And when you overload the system, something has to give."