The American Automobile Association (AAA) has released the findings of a test on automatic emergency braking systems, cautioning consumers about how these systems are not all created equal.

Some emergency braking systems are designed specifically to prevent a crash, while some are there to mitigate the effects of a crash. After testing five new 2016 car models, AAA says that the vehicles designed to prevent a crash reduced vehicle speeds by twice that of the systems designed to lessen the crash severity.

Of course, any reduction in speed before a crash is helpful, but the troubling part is that the agency found that nearly two-thirds of Americans familiar with the technology believe it will totally avoid a crash without driver intervention.

"The reality is that today's systems vary greatly in performance, and many are not designed to stop a moving car," said John Nielsen, AAA's managing director of Automotive Engineering and Repair.

At speeds under 30 mph, systems designed to avoid crashes were successful about 60 percent of the time, while the systems designed to only slow the car managed to totally avoid the crash about 33 percent of the time.

Speed it up to 45 mph and the cars designed to avoid collision reduced speeds by 74 percent and avoided the crash 40 percent of the time. Other crash mitigation systems only slowed the vehicle by 9 percent.

Automatic forward braking systems are set to spread through the market thanks to an agreement by automakers with the National Highway Traffic Safety Administration to make the technology standard on all new cars by 2022. Currently, about 10 percent of new vehicles offer the technology as standard, while more than half of the cars on the market have it available as an option.

"When shopping for a new vehicle, AAA recommends considering one equipped with an automatic emergency braking system," said Nielsen. "However, with the proliferation of vehicle technology, it's more important than ever for drivers to fully understand their vehicle's capabilities and limitations before driving off the dealer lot."