Quick facts about automatic emergency braking
In its current form, automatic emergency braking (AEB) first appeared on Volvo, Honda and Mercedes-Benz models. Despite Honda’s role in popularizing this technology, AEB has been predominantly found in high-end models over the past decade. However, it is now part of the standard equipment in such affordable entry-level models as the Nissan Versa.
AEB works with forward collision warning, often including a pedestrian detection system. For example, it can detect an object or a pedestrian in its path, warn the driver acoustically and apply the brakes. The automatic emergency braking is at least somewhat self-explanatory. However, if you are buying a car with this feature, you may want to know more about it. Read on and we’ll explain what it is, what it does, how it works and whether it helps.
What is automatic emergency braking?
Automatic emergency braking is an advanced safety technology that can slow or completely stop a vehicle without driver intervention. This means AEB can apply a vehicle’s brakes independently if the driver does not do so. The AEB systems found in most new cars bring the vehicle to a complete stop at slower speeds. Some systems operate at higher speeds.
In addition, some, but not all, systems can detect and brake pedestrians, cyclists and animals.
According to the Insurance Institute for Highway Safety (IIHS), an independent, nonprofit scientific and educational organization, the technology is already reducing accident rates for vehicles equipped with it by up to half. By 2029, the U.S. government will require automatic emergency braking systems in all new cars.
TIP: No advanced security system is 100% foolproof. This also includes automatic emergency braking. As a driver, it is still your responsibility to maintain control of your vehicle, regardless of what advanced safety technologies it may have. AEB is an assistant to the driver, not a replacement for the driver.
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How does automatic emergency braking work?
Depending on the system design, automatic emergency braking occurs using cameras, radar or other sensors. When these technologies detect the possibility of a collision with an object in your path, they automatically activate the braking system.
These systems do not guarantee that you will avoid a collision. Instead, in typical situations, they will try to stop your vehicle in a timely manner. At a minimum, they slow your vehicle to reduce the severity of the impact.
Tip: AEB only works if the camera, radar or sensors can identify objects. Extremely bright sunlight, heavy rain, packed snow, darkness and other variables affect automatic emergency braking.
Types of automatic emergency braking
The detailed description of the available AEB system types is quite simple, as there are actually only variations on two core types:
- Forward AEB
- Reverse AEB
Below we will list the different variations of forward AEB. Both types of systems use a combination of radar sensors, cameras and sometimes infrared technology to detect objects in their path. If the driver does not react to the potential danger, both systems apply the brakes to prevent the collision or lessen its severity.
What is forward automatic emergency braking?
The front AEB comes into action when there is a risk of a collision. This could be a vehicle that is stopped or moving more slowly.
What is forward automatic emergency braking with pedestrian detection?
Forward AEB with Pedestrian Detection is a forward AEB that detects pedestrians, bicycles and larger animals.
What is Low Speed Automatic Emergency Braking?
Automatic emergency braking at low speeds or in city traffic is designed for bumper-to-bumper situations. However, it also works in parking lots and other low-speed environments. For example, in a parking lot, AEB is activated when a car in front of you pulls out of the parking space.
What is automatic emergency braking at intersections?
Intersection AEB, or sometimes called Left Turn AEB, responds when you indicate a left turn at an intersection that puts your vehicle directly in the path of oncoming traffic.
What is High Speed Automatic Emergency Braking?
This is a forward AEB designed to bring a vehicle traveling at highway speeds to a complete stop.
What is rear automatic emergency braking?
Rear automatic emergency braking works the same as front automatic braking, except that it occurs when the vehicle is reversing. It reacts to objects such as cars moving across your path when reversing and to objects in your path.
What is forward collision warning?
Forward Collision Warning (FCW) uses sensors to detect objects on the road in front of you. It will sound an audible warning (or vibrate the driver’s seat or steering wheel if your car is equipped) if the system detects a possible accident. On most new cars, the FCW works hand in hand with your car’s AEB system. Regardless of whether the car in front of you stopped abruptly or you waited too long to apply the brake, this system warns you of an impending collision.
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Automatic emergency braking is often less effective in the dark
Most new cars have automatic emergency braking, and for good reason: the system helps save lives.
However, AEB systems tend not to be as effective in the dark. The IIHS examined these systems in 23 car models in nighttime conditions. The results show that most vehicles’ automatic emergency braking systems perform “poorly” in the dark, especially when it comes to detecting pedestrians.
Of the 23 models tested, the study found that only four vehicles received a “Superior” rating. These vehicles are the Ford Mustang Mach-E, Nissan Pathfinder, Toyota Camry and Toyota Highlander. The Chevrolet Malibu, Honda Pilot, Nissan Altima and Toyota Tacoma received no credit in vehicle testing.
Nevertheless, 19 of the 23 vehicles performed well in similar daily tests.
In 2019, another IIHS study concluded that the number of front-rear collisions decreased by 50% for vehicles with automatic emergency braking. There was also a 56% reduction in injuries from these types of collisions. When it comes to automatic reverse braking systems, there was a 78% reduction in accidents compared to vehicles that only had a rear view camera.
Automatic emergency braking false alarms
Sometimes this technology is activated when perceived threats are not real. In such cases, the sudden braking is usually only temporary. However, when this happens, it can rattle the driver’s nerves.
Occasionally, the system incorrectly recognizes a vehicle in an adjacent curved lane as an obstacle and triggers emergency braking. Dappled sunlight and reflections from signs can also trigger temporary activations. We found this out in our own driving tests. These false alarms are usually harmless – but underscore the importance of remaining vigilant behind the wheel.
Although automatic emergency braking is imperfect, it is still an effective safety feature.
If you suspect there is something wrong with your automatic emergency braking system, you can check our service and repair price guide to see how much it will cost. Then find the nearest car repair shops and make an appointment to have the work done.
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Editor’s Note: This article has been updated for accuracy since its original publication. Christian Wardlaw contributed to this article.