To find out how well the safety systems work in the real world, IIHS looked at police reports about rear-end collisions in 22 different states from 2010 through 2014. The agency looked at crash data for Acura, Honda, Mercedes-Benz, Subaru, and Volvo vehicles equipped with collision warning and braking systems, and then compared that with how often rear-end crashes were reported for cars without the feature.
IIHS says that if every car had pre-collision braking systems, there would have been 700,000 fewer rear-end crashes on American roads in 2013.
“As this technology becomes more widespread, we can expect to see noticeably fewer rear-end crashes,” IIHS chief research officer David Zuby said in a statement. “The same goes for the whiplash injuries that often result from these crashes.”
The agency notes that a warning system alone doesn’t make nearly as big of an impact in reducing crashes as systems that actually apply the car’s brakes.
“Even when a crash isn’t avoided, systems that have autobrake have a good chance of preventing injuries by reducing the impact speed,” IIHS vice president for research Jessica Cicchino said in a statement. “Still, it’s surprising that forward collision warning didn’t show more of an injury benefit.”
Drivers don’t like lane-departure warning
Another interesting finding from IIHS’s research is that drivers really hate lane-departure warning systems. In a study of 184 vehicles at a Honda dealership, IIHS found that only a third had the lane-departure warnings turned on. The agency says it suspects that’s because many drivers get annoyed by frequent alerts when they change lanes without using their turn signals.
“Lane departure warning has the potential to prevent a lot of the most serious crashes,” IIHS senior research scientist Ian Reagan said in a statement. “However, if people consider it a turn-signal nanny, they may not accept the feature.”