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Automatic emergency braking (AEB) isn’t perfect, but the technology is improving, according to a recent study conducted by AAA. The research comes on the heels of a new federal rule requiring all vehicles to have the most robust version of AEB by 2029.

AAA wanted to see how newer vehicles with AEB fared compared to older models with the technology. AEB uses forward-facing cameras and other sensors to automatically tell the car to apply the brakes when a crash is imminent. And according to the test results, newer versions of AEB are much better at preventing forward collisions than older versions of the tech.

The motorist group conducted its test on a private closed course using older (2017–2018) and newer versions (2024) of the same three vehicles: Jeep Cherokee, Nissan Rogue, and Subaru Outback. Each vehicle was tested at 12mph, 25mph, and 35mph to see how well AEB performed at different speeds. And a fake vehicle was placed in the middle of the road to see whether AEB could prevent a collision.

Unsurprisingly, the newer models performed a lot better than the older ones: 100 percent of the 2024 vehicles braked before a collision, as compared to 51 percent of the older vehicles.

That’s an improvement over similar tests conducted by AAA in 2022 in which AEB was better at preventing low-speed collisions than those at more normal speeds.

Still, this more recent test only involved forward collisions. Past AAA studies found AEB to be ill-equipped at preventing other common types of crashes, like T-bone collisions and left turns in front of approaching vehicles.

“Since we began testing AEB in 2014, the advancements by automakers are commendable and promising in improving driver safety,” said Greg Brannon, director of automotive engineering research. “There is still significant work ahead to ensure the systems work at higher speeds.”

It was a positive sign that AEB is improving, considering the National Highway Traffic Safety Administration (NHTSA) finalized a new requirement for all light-duty vehicles to have robust AEB systems by 2029. Around 90 percent of vehicles on the road today come standard with AEB, but the new rule requires automakers to adopt a more robust version of the technology that can stop vehicles traveling at higher speeds and detect vulnerable road users, like cyclists and pedestrians, even at night.

Even so, automakers are scrambling to put the brakes on the new rule’s adoption. Earlier this year, the Alliance for Automotive Innovation, which represents most of the major automakers, sent a letter to NHTSA arguing that the final rule is “practically impossible with available technology” and urging the agency to delay its implementation.