Killer in the Backseat
The legend involves a woman who is being followed by a strange car or truck. The mysterious driver flashes his high beams, tailgates her, and sometimes even rams her vehicle. When she finally makes it home, she realizes that the driver was trying to warn her that there was a man (a murderer, rapist, or escaped mental patient) hiding in her back seat. Every time the man sat up to attack the driver, her pursuer scared him.
In some versions the woman stops for gas, and the attendant asks her to come inside to sort out a problem with her credit card. Inside the station, he asks if she knows there’s a man in her back seat.
The story is often told with a moral. The attendant is often a lumberjack, a trucker, or a scary-looking man; someone the driver distrusts without reason. She assumes it is the attendant who wants to do her harm, when in reality it is he who saves her life.
As a result of this urban legend, some people became paranoid and would check their backseats before entering their cars. However, it would be unlikely for an adult to hide in the backseat of a car without being noticed straight away by the driver.