Automatic Emergency Braking 

Illustration depicting automatic emergency braking systems

What are automatic emergency braking systems?

Automatic emergency braking (AEB) systems detect an impending forward crash with another vehicle in time to avoid or mitigate the crash. These systems first alert the driver to take corrective action to avoid the crash. If the driver’s response is not sufficient to avoid the crash, the AEB system may automatically apply the brakes to assist in preventing or reducing the severity of a crash. The National Highway Traffic Safety Administration believes these technologies represent the next wave of potential significant advances in vehicle safety. AEB systems, such as dynamic brake support (DBS) and crash imminent braking (CIB), have the potential not only to save lives but also to reduce moderate and less severe rear-end crashes that are common on our roadways.

Dynamic Brake Support

Illustration depicting additional force being applied to vehicle brakes
If the driver brakes but not hard enough to avoid the crash, dynamic brake support (DBS) automatically supplements the driver’s braking in an effort to avoid the crash.

Crash Imminent Braking

Illustration depicting vehicle brakes being applied without driver interaction
If the driver does not take any action to avoid the crash, crash imminent braking (CIB) automatically applies the vehicle’s brakes to slow or stop the car, avoiding the crash or reducing its severity.
Illustration depicting a two vehicle accident

Why is NHTSA focusing on AEB technology? Are there significant benefits?

In 2012, one-third of all police-reported crashes involved a rear-end collision with another vehicle as the first harmful event in the crash, and NHTSA believes that advanced crash avoidance and mitigation technologies like AEB systems could help in this area. NHTSA’s extensive research on this technology and on relevant performance measures showed that a number of AEB systems currently available in the marketplace are capable of avoiding or reducing the severity of rear-end crashes in certain situations.
Illustration depicting numerous vehicles

What is the current state of the technology?

Two AEB systems, crash imminent braking (CIB) and dynamic brake support (DBS), have been available on some vehicle models in the United States since 2006.
Illustration depicting a small monetary amount added to a vehicle

How much will these technologies add to vehicle cost?

Today, advanced crash avoidance technologies, such as CIB and DBS systems, are typically included in safety technology packages as optional features. Manufacturers are using a number of different sensor combinations in production-level AEB systems. The agency conducted a cost analysis of several production-level systems and found that the system cost varies significantly depending on the type and number of sensors used.
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