Luxury vehicles topped the latest Insurance Institute for Highway Safety ratings for cars with a system that prevents front-end collisions. The insurance industry trade group also said such safety systems work better than first thought at preventing crashes.
Four of the 24 vehicles tested earned perfect scores on this test of forward collision avoidance systems. They were the 2014 BMW 5 series sedan, BMW X5 sport-utility vehicle, Mercedes-Benz E-Class sedan and the 2015 Hyundai Genesis sedan.
But there was a catch. These systems don't come standard on all the vehicles and the ones that worked best came with special camera and radar options that added to the price of the vehicle.
Shoppers concerned about which options offer the highest-rated systems need to research the packages. Some versions of the BMW 5 series, for example, are rated superior while others have a lower rating.
In all, four other models were not perfect but still earned the highest rating of superior, 13 earned an advanced rating and three earned a basic rating.
The institute rated a vehicle as basic, advanced or superior for front crash prevention depending on whether it offers automatic braking as part of the forward collision avoidance system and if so, how effective it is preventing crashes in tests at 12 and 25 mph.
The insurance group first started testing the crash avoidance systems in September and is already seeing automakers make adjustments to their cars to improve the systems.
"BMW and Lexus, for example, have added more braking capability to their systems, which has paid off in higher ratings," said David Zuby, IIHS executive vice president and chief research officer.
"We know that this technology is helping drivers avoid crashes," Zuby says.
Even when the automatic braking isn't strong or fast enough to avoid a crash, the system is effective at slowing the car.
"Reducing the speed reduces the amount of damage that occurs to both the striking and struck cars and reduces injuries to people in those cars," Zuby said.
A different test of a Honda Accord – a vehicle that doesn't have the automatic braking system – found that just warning the driver of the potential of a crash is an effective safety measure.
Honda's system – which also includes an alert when the car veers out of its traffic lane -- reduced insurance claims for damage to other vehicles by 14%. It cut claims for injuries to occupants of the equipped vehicles by 27% and claims for injuries to other road users by 40%.
"This was our first opportunity to study advanced crash avoidance technology on a high-volume vehicle, and the results are impressive," said Matt Moore, a researcher for the insurance group.
Front crash prevention systems use various types of sensors, such as camera, radar or laser, to detect when the vehicle is getting too close to one in front of it. The systems use lights, chimes and sometimes vibration to alert a driver to a hazard. Many systems brake the vehicle autonomously if the driver doesn't respond.
The other vehicles getting a superior rating in the latest tests included the Buick Regal, Cadillac CTS, Cadillac XTS and Chevrolet Impala.
Those rated as advanced were the BMW 2 series, 3 series, 5 series and X5, Buick LaCrosse, Lexus IS and GS, Audi A3 and A6, Dodge Durango, Mercedes-Benz GLA and Infiniti QX50 and QX70.
Those rated basic were the BMW 3 series, Infiniti Q70 and Toyota Avalon.
"Sorting through the various trade names and features can be confusing, even if you're looking at models from the same manufacturer. Before buying, consumers should consult the IIHS ratings to find out if the specific model they are considering comes with a top-rated front crash prevention system," Zuby advises.
To see ratings by make and model go to iihs.org/ratings, and to check availability of crash avoidance features go to iihs.org/crash_avoidance.