Feds' new emergency braking rule to test auto industry

A federal rule that requires automatic emergency braking systems in cars and light trucks by 2029 could be a tough compliance hurdle for automakers but further the industry's efforts to use technology to improve safety.

While experts say automatic emergency braking systems are customary in most vehicles, the rule — which was finalized by NHTSA on Monday — has enhanced speed and nighttime requirements that might push the envelope on available technology.

"It's no longer going to be enough to simply say, 'You know, our vehicles have an AEB system that works under some limited circumstances,' " said William Wallace, associate director of safety policy at Consumer Reports. "It's now going to be critically important for every automaker to have highly effective automatic emergency braking, including at higher speeds and in cases with pedestrians."

Under the final rule, all vehicles must be able to automatically stop and avoid a collision with another car at speeds of up to 62 mph. The system must apply the brakes automatically at up 90 mph when a collision with another car is "imminent," and at 45 mph when a pedestrian is detected.

"The faster you're going, the farther down the road you have to be able to see the thing that [the system] is assessing," said Carol Flannagan, a professor at the University of Michigan's Transportation Research Institute. "It's a harder job for the sensor."

The Insurance Institute for Highway Safety reported last week that in its front-crash collision test, automatic emergency braking systems in vehicles it classifies as small SUVs performed significantly worse when speeds were increased from 12 and 25 mph to 31, 37 and 43 mph. All vehicles tested at the lower speeds received a "superior" rating, while only one vehicle tested at the higher speeds ranked "good."

"I think the automakers are in good position to respond to this new regulation," said David Zuby, chief research officer at IIHS. "What's tricky about the regulation is that it does now sort of raise the bar for the level of performance that [NHTSA] is asking for from these systems."

The speed requirements set a tough but feasible standard for automakers, especially since many already have to comply with stricter European regulations, Wallace said.

"Already in the last few years, AEB technology has improved significantly. It will continue to improve, especially given the opportunity to have five years for implementation," he said.

The rule requires the systems to be able to detect pedestrians in nighttime conditions. Smaller vehicles, such as motorcycles, and pedestrians are more difficult for systems to detect, according to IIHS.

Automatic braking systems that rely on traditional cameras are usually less effective at night. Adjusting to NHTSA's rule will likely require increased investment from automakers, experts say.

"Automakers do have a ways to go when it comes to improving the performance of AEB at nighttime with respect for pedestrians," Wallace said. "There are various advances in the marketplace and various technologies that could be used in order to improve the performance of these systems."

Improvements could include using lidar sensors instead of radar and camera detection or using thermal technology to detect body heat, according to experts.

Automatic emergency braking systems typically prevent front-to-rear crashes 50 percent of the time, Zuby said. NHTSA estimates the rule will save 360 lives and prevent 24,000 injuries annually.

The systems are not without their risks. Last month, NHTSA upgraded a probe into nearly 3 million Honda Motor Co. vehicles after reports of unexpected activation of emergency braking. The defect resulted in 31 reported crashes and 50 injuries, according to NHTSA.

"That's not wildly common, but automation failure is something people have very low tolerance for," Flannagan said.

Under the final rule, vehicles will need to pass a series of tests to prevent such false activations.

The tightened requirements pose significant benefits, particularly for driver-assistance technologies — such as Tesla's Autopilot and Ford's BlueCruise — which have caused collisions.

"The automatic braking could help address some of these crashes that occur because the automated system isn't following the lane, and the driver is not paying attention to the fact that it's not following in the lane," Zuby said.