Automatic Emergency Braking Systems (AEB), systems that automatically brake if the driver does not intervene to avoid a collision or reduce its severity, have proven to be very helpful in reducing the number of accidents. A previous IIHS study found that cars with automatic emergency braking had 50% fewer rear-end collisions. Pedestrian detection systems are also very effective: equipped cars have 27% fewer collisions with pedestrians. But there are limits to these systems, especially in areas where collisions are quite common. IIHS has previously noted that poor light can reduce the effectiveness of these systems. Now AAA has found that higher speeds and certain types of collisions need improvement.
The situations AAA tested include rear-end collisions at speeds higher than IIHS currently tests. The IIHS tests at speeds up to 25 mph. In its research, AAA found that 60% of rear-end injury crashes occur in areas with speed limits between 30 and 45 mph. As such, it tested systems at 30 mph and 40 mph with stationary dummy vehicles. AAA also tested with the other two most common two-vehicle injury crashes that, when combined with rear-end collisions, result in 79% of injury-causing wrecks: T-bone collisions and collisions with an oncoming vehicle running over traffic. These were tested at 30 mph. The test vehicles were popular models with standard automatic emergency braking that are likely to have more people and that spanned a wide variety of designs and suppliers: a 2022 Chevy Equinox, 2022 Ford Explorer, 2022 Honda CR-V and 2022 Toyota RAV4.
While these collision avoidance systems were designed to avoid low-speed collisions, they still proved effective in reducing the severity of rear-end collisions. At a speed of 30 mph, each car warned the driver of an impending collision and applied the brakes. The Toyota and Ford also managed to avoid a crash in all five attempts. The Equinox collided once and the CR-V twice, but in all those situations, both cars reduced speed by more than 20 mph, reducing the severity.
Increasing speeds to 40 mph resulted in more collisions, yet each car issued a warning and braked. The Ford cut speeds by 31.8 mph, despite hitting every time. The Equinox dropped speeds by 17.5 mph, which was less than the 30 mph test. The CR-V avoided collisions twice and reduced its speed in collisions by an average of 50.8 km/h. The RAV4 had a somewhat confusing result. It managed to stop completely four out of five times. But the time he struck, his speed only dropped by 7.9 mph.
The advantage in rear-end collisions is that automatic emergency braking systems are less effective at completely avoiding a collision at higher speeds, but can still significantly reduce the severity of the collision. Automakers are also working on systems that are more effective at higher speeds. In fact, Chevy offers a system called Enhanced Automatic Emergency Braking, designed for higher speeds. It is offered as an option on some models, such as the Tahoe/Suburban, Bolt EUV and Traverse. Although actual availability may be low due to chip delivery issues. The IIHS also announced earlier this year that it wants to increase its AEB test speeds. So there’s a good chance that performance in this area, while not terrible, is likely to improve significantly in the near future.
While the results for rear-end collisions are not too bad, the other types of collisions are a problem area for current AEB systems. With cross traffic T-bone collisions, and situations with another car turning in front of a driver, all vehicles hit every time. And in each test, each car failed to warn the driver or apply the brakes.
This is somewhat understandable, as most of these systems are only designed to avoid rear-end collisions. Only recently have these systems begun to detect pedestrians and cyclists, and the ability to detect cars or pedestrians in the car’s path when cornering at intersections. It is also likely that these situations are more difficult to program to recognize the car and do so without causing false positives.
That said, since these types of crashes are responsible for the majority of injuries, it’s clear that automakers should focus on offering systems that can prevent these crashes.
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