As told by Emily Dunbar:
One night a woman went out for drinks with her girlfriends. She left the bar fairly late at night, got in her car and onto the deserted highway. After a few minutes she noticed a lone pair of headlights in her rear-view mirror, approaching at a pace just slightly quicker than hers. As the car pulled up behind her she glanced and saw the turn signal on — the car was going to pass — when suddenly it swerved back behind her, pulled up dangerously close to her tailgate and the brights flashed.
Now she was getting nervous. The lights dimmed for a moment and then the brights came back on and the car behind her surged forward. The frightened woman struggled to keep her eyes on the road and fought the urge to look at the car behind her. Finally, her exit approached but the car continued to follow, flashing the brights periodically.
Through every stoplight and turn, it followed her until she pulled into her driveway. She figured her only hope was to make a mad dash into the house and call the police. As she flew from the car, so did the driver of the car behind her — and he screamed, "Lock the door and call the police! Call 911!"
When the police arrived the horrible truth was finally revealed to the woman. The man in the car had been trying to save her. As he pulled up behind her and his headlights illuminated her car, he saw the silhouette of a man with a butcher knife rising up from the back seat to stab her, so he flashed his brights and the figure crouched back down.
The moral of the story: Always check the back seat!
Analysis: In another common variant of this legend, the imperiled female (and it's always a female, please note) pulls into a gas station and is frightened by the odd behavior of the attendant, who keeps trying to get her to leave the car and join him in the office. It turns out he has glimpsed a knife-wielding murderer in the backseat and is trying to save her life!
Folklorists have traced the legend back to the 1960s and believe it may have been inspired by a vaguely similar real event in 1964 involving the discovery by a New York City policeman of an escaped murderer hiding in the backseat of his (the cop's) own car.
"The Killer in the Backseat" was among the legendary horror stories dramatized in the 1998 film Urban Legend. Let us not assume, however, that real-life evildoers never lie in wait for their victims in the backseats of vehicles. As reported in the Decatur Daily News on September 14, 2007, a female college student in Alabama was threatened by a man with a gun who popped up suddenly in the backseat of her SUV. She escaped, fortunately, by slamming on the brakes and bolting from the car.