Not every car has one.
Right now it's kind of a luxury.
But a new law will soon require every car to have one in the name of safety.
The U.S. Department of Transportation issued a new rule requiring all cars and trucks less than 10,000 pounds, including buses to include rear visibility technology.
This rule affects models made after May 1, 2018.
These cameras expand the field of vision by 10 to 20 feet.
"I think it's a good thing anytime you can do something to possibly save somebody's life," says Washington County Sheriff Larry Mincks. "I would also like to see the sensors installed with that. If you are going to take the step to do the cameras, why not put the sensors in also."
Costing around $150 per car, the sheriff says it's worth the extra money for the safety.
Back up accidents cause an average of 210 deaths and 15,000 injuries a year.
Most of those victims are small children and the elderly.