Those rearview cameras in late-model vehicles are doing their job, according to a new study.

Rearview camera screen (Jeep)

AAA studied 17 equipped vehicles from 11 manufacturers, and found the cameras improved rear visibility by an average of 46 percent.

"The rearview cameras did, in fact, aid in visibility," said Tracy Noble, AAA spokesperson.

Noble said the backup cameras worked best in hatchbacks, large trucks and SUVs. In the survey, ratings of reliability and effectiveness ranged from 36 percent in smaller sedans to 75 percent in the larger vehicles.

But Noble also said the cameras are just one safety tool that helps a driver, pointing out that they do not provide 100 percent rear visibility.

"You need to still turn your head, use your mirrors and then use the camera as an additional tool," she said.

AAA made the point that rain, snow, ice or slush may cloud the camera's lens and blur the image a driver sees, so reliability may also be dependent on weather conditions. Those conditions aside, the cameras seemed to work best at displaying the first 10 feet behind a vehicle -- the biggest danger zone when backing up.

The camera tests were conducted by the Automobile Club of Southern California's Automotive Research Center.

Noble also suggested the cameras will come in handy in crowded parking lots at shopping centers this holiday season, hopefully preventing backup mishaps.

The National Highway Traffic Safety Administration requires cameras with a rear view to be installed in passenger vehicles beginning with the 2016 model year, aiming for full compliance by May 2018.