‘Braking Bad’ – Automatic Emergency Braking Doesn’t Always Prevent Crashes

Automatic emergency braking technology, now standard equipment on most new cars sold in the United States regardless of price, was designed to help prevent crashes or reduce their severity, but it doesn’t always work when it is most needed.

That is the main take-away of new crash test results recently released by the AAA automotive group that found that current systems typically function better at spotting stationary vehicles when traveling at lower speeds than they do detecting moving vehicles and when traveling at higher speeds.

“Automatic Emergency Braking does well at tackling the limited task it was designed to do,” Greg Brannon, director of AAA’s automotive engineering and industry relations, said in a statement. “Unfortunately, that task was drawn up years ago, and regulator’s slow-speed crash standards haven’t evolved.”

The technology, known as AEB, applies a vehicle’s brakes automatically in order to detect an imminent crash. Its on-board cameras and sensors tell the car to initiate the brakes or increase the braking power if the driver does not take sufficient action when a crash is about to happen.

Researchers noted that AEB has successfully reduced rear-end crashes at slower speeds in recent years, but two of the most common deadly crashes currently occurring at intersections are T-bones and left turns in front of oncoming vehicles. From 2016 to 2020, for example, these two types of crashes accounted for nearly 40 % of total fatalities in crashes “involving two passenger vehicles during which the striking vehicle did not lose traction or leave the roadway before the collision,” according to the report.

For its analysis, AAA selected four 2022 vehicles to test AEB technology, two with each driver monitoring design type: camera-equipped and input from the steering wheel. The models were: Chevrolet Equinox LT with “Chevy Safety Assist”; Ford Explorer XLT with “Pre-Collision Assist with Automatic Emergency Braking”; Honda CR-V Touring with “Honda Sensing”; and Toyota RAV4 LE with “Toyota Sensing.”

Test vehicles were assessed encountering a stationary vehicle at higher, more realistic speeds than previously (30 and 40 mph compared to 12 and 25 mph), and also when confronting moving vehicles in their path in common collision scenarios found at intersections – T-bone and unprotected left turn (test vehicle turning left in front of an oncoming car).

“It struggled with the former and failed with the latter,” according to the study: “In both the T-bone and left-turn in front of oncoming vehicle tests, crashes occurred 100% of the time. AEB failed to alert the driver, slow the vehicle’s speed and avoid the crash.”

As a result, the automotive group said it strongly urges automakers to improve AEB systems to assist drivers in intersection-based crash scenarios, and for drivers to recognize the technology’s limitations and remain alert and engaged when behind the wheel.

“Testing requirements for this technology, or any vehicle safety system for that matter, must be updated to handle faster, more realistic speeds and scenarios with the greatest safety benefit for drivers,” Brannon added.

For more details about the testing and to read the full report, click here.