Automotive research showing the life-saving benefits of a host of advanced safety systems is starting to pile up, with the latest study concluding that lane-departure warning systems reduce car crashes—saving lives and reducing injuries.

The new research from the Insurance Institute for Highway Safety found that if all U.S. passenger vehicles were equipped in 2015 with a lane-departure warning system, nearly 85,000 crashes and more than 55,000 injuries would have been prevented that year.

“This is the first evidence that lane-departure warning is working to prevent crashes of passenger vehicles on U.S. roads,” says Jessica Cicchino, the IIHS vice president for research. “Given the large number of fatal crashes that involve unintentional lane departures, technology aimed at preventing them has the potential to save a lot of lives.”

Lane-departure warning systems lower the rates of three types of passenger car crashes—single-vehicle, side-swipes, and head-on—by 11 percent and cut injuries in those same types of crashes by 21 percent, the study found. 

Points for Safety Systems

The technology, growing in popularity and availability, alerts drivers with an audible, visible, or tactile warning (seat or steering wheel shakes) if the driver lets the vehicle drift out of its lane.

Other crash-avoidance systems, such as forward-collision warning and automatic emergency braking, have shown the same kind of dramatic impact on reducing crashes, but until now there wasn’t clear data showing the effect of lane warnings.

More on Car Safety

Consumer Reports awards extra points to a vehicle's Overall Score if all versions come with standard forward-collision warning and automatic emergency braking.

As other advanced safety systems, including lane-departure warning, lane-keeping assist, and blind-spot monitoring, are proved to reduce crashes, injuries, and deaths, CR plans to evaluate how much those systems might add to a vehicle's score.

The IIHS analysis controlled for driver age, gender, insurance risk level, and other factors that could affect the rates of crashes per insured vehicle year.

Owners Endorse Safety Systems

CR readers have given mixed reviews for lane-departure warning systems. But overall, most of the car owners reported being happy with the systems. 

In a recent survey of more than 57,000 CR subscribers, 70 percent of owners reported that they liked the technology, and 12 percent said that it had helped them avoid a crash.

For specific brands, more than 77 percent of Cadillac, Hyundai, and Tesla owners said they were very satisfied with their lane-departure warning system, followed by Lexus, Dodge, Chrysler, and Jeep owners. 

The types of complaints about the systems suggest that some fine-tuning of the warning system technology might be required. Owners in the CR survey said that warnings appeared inconsistently, or that the system had produced false alarms.

The results, though positive, were less dramatic than in other studies that focused on a specific country, vehicle, or type of driver. A 2015 study of lane-departure warning systems in heavy-duty U.S. trucks found that the crash rate was cut almost in half when the system was present. A study in Sweden of Volvo cars with the technology found that injury-producing crashes fell 53 percent.

One reason the benefit may be less dramatic for U.S. passenger vehicles is that drivers frequently turn off lane-departure warning systems, possibly because they’re irritated by false warnings, IIHS says. Another factor could be that lane-departure warning requires an appropriate response from drivers. Earlier IIHS research showed that in about one-third of lane-drift crashes, drivers were physically incapacitated, either from falling asleep, having a medical emergency, or blacking out from alcohol or drug use.