Automatic Emergency Braking (AEB) systems have huge institutional support. Pedestrian and bicyclist safety advocacy groups have been pushing for their adoption since their introduction in 2008. The Insurance Institute of Highway Safety (IIHS) has also gotten on board. Thanks in part to this highly influential organization, nearly 100 passenger vehicle models in America will come equipped with the systems. They’re already required equipment in Japan and the European Union.
As the, “IIHS is leading the way in pressuring automakers to make cars and SUVs safer for pedestrians and cyclists,” according to League of American Bicyclists policy director Ken McLeod, the systems are justifiably coming under more scrutiny. Recent testing by the American Automobile Association (AAA) showed increased capabilities as well as some limitations:
AAA’s Vehicle-on-Vehicle Testing
Automatic Emergency Braking Systems Have Come a Long Way
2024’s tested AEB systems were 100% effective at preventing collisions with another vehicle at speeds up to 35 mph. Older systems prevented only 51% of collisions up to 35 mph.
Brand Matters
The performance of older models was starkly divided by brand. Older model Subaru vehicles performed just as well as 2024 models up to 35 mph, while older model Jeeps had collisions at any speed, and older Nissans prevented no collisions above 12 mph.
The Systems Still Struggle at Higher Speeds
The AEB systems that performed well up to 35 were also tested at 45 and 55 mph. Every vehicle either experienced or would have experienced a collision at 55 mph.
But What About Pedestrians?
In 2022, there 1,201 pedestrian deaths in the state of California. With a rise in pedestrian accidents across the US, vulnerable road users are pushing for this technology to be mandated, but technological limitations are still hitting them the worst.
Road Conditions
Modern systems have improved hugely on the IIHS’s test track, but they only test in broad daylight on a straight stretch of track. 75% of pedestrian road deaths happen at night, and in a range of road conditions. A straight path in daylight hours doesn’t reflect how AEB systems interact with walkers and bikers.
Night
Considering 75% of pedestrian deaths happen at night, AAA‘s testing results are disturbing. Even the newest systems basically don’t work at all at night. Though radar sensors have been added to most vehicles, they still appear to be greatly dependent on visual feedback.
Disappointing Performance Overall
In more realistic road conditions against pedestrians, no Automatic Emergency Braking system avoids collisions even half of the time. Often, they don’t even meaningfully reduce speed before impact.
AEB systems are improving and are essentially standard, if not mandatory, equipment on passenger vehicles in America. They are quite good at avoiding or mitigating the damage of vehicle-on-vehicle collisions even at high speeds. Unfortunately, they are still relatively poor at reacting to the groups likely to be harmed the most by a vehicle impact. Despite improvements, effectiveness at higher speeds, at night, and in more dynamic road conditions continues to lag.