ARLINGTON, Va., (WUSA) -- Front crash prevention systems warn drivers that they're about to hit something.
Auto braking systems make cars stop by themselves and they can add thousands of dollars or more to the cost of a new car.
But which system works best?
The Insurance Institute for Highway Safety tested more than 70 new cars and SUVs, staging crashes at 12 and 25 miles per hour.
Researchers say the safety systems that performed the best combined a warning system and auto braking.
"There's the warning, and there's the auto braking. the vehicle stopped by itself," says David Zuby.
Researchers says a 25 mile per hour crash between a Mercedes C Class and a Chevy Malibu can cause more than $28,000 in damage to both vehicles.
In a 12 mile per hour crash involving a Mercedes with an auto braking system brings the damage cost to about $5,700.
The best performing vehicles at the top of the Institute's list are the Subaru Legacy and Subaru Outback, which researchers say earned perfect scores.
IIHS Crash Avoidance Tests
The Insurance Institute for Highway Safety wants you to get the littlest bang for your bucks.
The technology is mostly optional.
The cost of the crash avoidance systems could add up to thousands of dollars depending on how advanced the technology is. And, about five to 10 percent of new cars are now being sold with these systems.