NHTSA finalizes emergency braking rule for cars and light trucks

To further decrease the amount of deaths and injuries caused by roadway collisions, National Highway Traffic Safety Administration (NHTSA) has finalized a new Federal Motor Vehicle Safety Standard, FMVSS No. 127, to make automatic emergency braking (AEB) standard on passenger cars and light trucks (under 10,000 lb. GVWR) by September 2029. These AEB systems must also detect pedestrians—during daytime and at night—as well.

NHTSA defines a compliant AEB systems as one that “uses various sensor technologies and sub-systems that work together to detect when the vehicle is in a crash imminent situation, to automatically apply the vehicle brakes if the driver has not done so, or to apply more braking force to supplement the driver's braking.”

FMVSS No. 127 states that the system must prevent a car or light truck from making contact with the vehicle in front of it up to 62 mph, and automatically apply the brakes up to 90 mph if “a collision with a lead vehicle is imminent.” Furthermore, the brakes must activate at 45 mph when the sensors detect a pedestrian.

NHTSA projects that annually more than 360 deaths and 24,000 injuries will be prevented with the measure. Overall, the Department of Transportation agency estimated motor vehicle crashes were responsible for 40,990 fatalities, down 3.6% from 2022.

“The new vehicle safety standards we finalized today will save hundreds of lives and prevent tens of thousands of injuries every year,” said U.S. Transportation Secretary Pete Buttigieg, who previously stated the DOT’s target is “zero deaths.”

This rule began as a provision in the Bipartisan Infrastructure Law and is part of the DOT’s National Roadway Safety Strategy. A final rule for mandating AEBs on medium- and heavy-duty trucks, FMVSS No. 128, is expected later this year. NHTSA data indicated there were 5,788 large truck crash fatalities in 2022, an increase of 2% over 2021.

NHTSA Deputy Administrator Sophie Shulman noted the time is right for AEB mandates.

“Automatic emergency braking is proven to save lives and reduce serious injuries from frontal crashes, and this technology is now mature enough to require it in all new cars and light trucks. In fact, this technology is now so advanced that we’re requiring these systems to be even more effective at higher speeds and to detect pedestrians,” she said. “Most new vehicles already come with AEB, and we expect that many cars and light trucks will be able to meet this standard ahead of the deadline, meaning even more lives will be saved thanks to this technology.” 

The National Safety Council applauded NHTSA's actions and plans to meet with federal legislators during Infrastructure Week (starting May 13) in Washington D.C. to discuss other "issues impacting pedestrians and other vulnerable road users," NSC stated.

“AEB systems are a much-needed, lifesaving feature that not only protect occupants but those outside of the vehicle," said Mark Chung, executive vice president of roadway practice at NSC. "Thanks to this standard, they will be the standard in passenger cars and lights trucks by September 2029. We are thrilled with this step forward and look forward to NHTSA and FMCSA publishing a final rule to include this lifesaving technology in heavy vehicles.”