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As vehicles continue to improve with advanced technologies, features such as automatic emergency braking (AEB) systems are at the forefront of car safety. AEB systems debuted in the mid-2000s and are responsible for saving lives and preventing highway mishaps. They have become so beneficial that they’re now commonplace in most models.

In an agreement with the National Highway Traffic Safety Administration (NHTSA), by September 1, 2022, automakers will include automatic emergency braking systems as standard equipment in almost all new vehicles sold in the United States. AEB in new vehicles will become mandatory by 2025.

What is automatic emergency braking?

Automatic emergency braking, AEB
A Volkswagen Passat with automatic emergency braking (AEB) technology | Andreas Arnold/Bloomberg via Getty Images

AEB systems can detect a potential collision and automatically apply the vehicle’s brakes. “By eliminating the human reaction time involved in braking, an AEB system can help reduce the likelihood of a crash or at least lessen the severity of the impact,” Erie Insurance explains.

Though AEB systems vary by manufacturer, they operate under the same principle. A series of cameras or sensors, or both, will detect an oncoming forward collision. The vehicle software analyzes the possibility of a crash, evaluating several data points, including the distance of surrounding objects and the current rate of travel. If a potential threat exists, the AEB system automatically engages the brakes, slowing the vehicle to avoid impact.

Here are four types of AEB systems with varying levels of performance capabilities:

1. Low-speed AEB

A low-speed AEB system is designed to perform at speeds under 55 mph and will not engage during highway driving. Low-speed AEB is typically effective for preventing collisions in heavy city traffic and parking lots.

2. Full-speed AEB 

Full-speed AEB systems function best at highway speeds, using advanced sensors to predict vehicle movement farther down the road. The computer sees the impeding traffic ahead and slows the vehicle to react accordingly.

JD Power points out that while the sensing technology helps “see” farther down the road at typical travel speeds, “in most higher-speed situations, AEB can only slow your vehicle as much as possible before impact instead of bringing it to a stop in time to avoid a collision.”

3. Reverse AEB

Reverse AEB systems work when the vehicle backs up and are especially useful in driveways and parking lots. They’re beneficial in preventing low-speed collisions and typically work with rear cross-traffic alert systems. The auto-braking system will stop the vehicle before hitting the object in its path. 

4. Pedestrian detection

AEB systems are invaluable for detecting cyclists and pedestrians that might cross in front of your vehicle, helping to avoid unnecessary collisions. The advanced safety equipment also works in unison with forward-collision warning (FCW) technology to help detect large animals, such as deer, reducing the chance of impact. 

FCW uses a sound or visible signal to alert the driver to a forthcoming collision, giving them the chance to hit the brakes. If the driver doesn’t react fast enough, the AEB kicks in, stopping the vehicle before impact.

Do automatic emergency braking systems work?


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MotorTrend points out that while “the technology is not advanced enough to detect and mitigate every potential impact,” an AEB system “really works in those moments when a split second or a few feet make all the difference.”

According to the Insurance Institute for Highway Safety (IIHS), automakers’ commitment to improving driver safety with standard AEB systems will “prevent 42,000 crashes and 20,000 injuries by 2025.” The institute claims that “the estimate is based on IIHS research that found that front crash prevention systems with both forward collision warning and automatic emergency braking cut rear-end crashes by half.”