Autonomous Vehicle Brakes: What Is It and how Does it Work?

Autonomous Vehicle Brakes: What Is It and how Does it Work?

Autonomous Emergency Braking (or AEB) is a pioneering safety system “designed to avoid low-speed collisions, or reduce the severity of an impact.”

While this technology is being deployed in the newest range of some ranges of motor vehicles, it is still within its infancy stages with most other vehicle manufacturers. Thanks to Land Rover for the information below!

What is AEB?

AEB is intended to support the driver in a raft of different scenarios but is never meant to replace the person behind the wheel who always has absolute control. 

How does AEB Work?

“A tiny stereo video camera mounted next to the rear-view mirror scans the road and senses when stationary or slow-moving traffic appears ahead. The system monitors the gap between you and the vehicle ahead: if this reduces and you do not react by applying the brakes, the system automatically applies maximum braking, using the Anti-lock braking system to slow the car as much as possible.”

What can I expect to see if AEB is activated?

“When a collision risk is identified but is still avoidable, a Forward Alert (FA) warning will be displayed in the Instrument Cluster Message Centre. If you are travelling above 35 km/h you will also hear an audible alert to indicate the risk. After the event, you will see “AEB was activated” in the message centre.

During an AEB intervention you will receive the following messages displayed:

  • 5 km/h to 35km/h: “AEB is active” during the intervention and then “AEB was activated” afterwards.
  • 35km/h to 80 km/h: “Forward Alert” message and a red icon before the intervention and for the full duration of the intervention, then “AEB was activated” afterwards.

Be aware: Autonomous Emergency Braking will not work at speeds above 80 km/h.


Which Cars have AEB?

Autonomous Emergency Braking is one of the standard safety features on Land Rovers New Discovery Sport. However, in certain countries, it is only available as an optional upgrade.

Other motor vehicles fitted with this technology include:

AEB for Audi

2010: “Pre sense” autonomous emergency braking system uses twin radar and monocular camera sensors and was introduced in 2010 on the 2011 Audi A8″. “Multicollision brake assist” uses controlled braking manoeuvres during the accident to aid the driver. Both systems were introduced on the Second generation Q7.


AEB for BMW:

2012: BMW introduced two systems on the 7 Series. “Active Protection” detects imminent accidents to pretension safety belts, close windows and moonroof, bring backrest of the front passenger seat to an upright position, and activate post-crash braking. A driver drowsiness detection includes an advice to take a break from driving. An “Active Driving Assistant” combines lane departure warning, pedestrian protection, and city collision mitigation.

In 2013, “Driving Assistant Plus” was introduced on most models combining the front-facing camera, lane-departure warning, and in some cases front radar sensors to detect vehicles ahead. Should the driver not react to the warning of a potential collision, the system would gradually prime brake pressure and apply – with maximum deceleration power – if necessary? In the case of a crash, the system can bring the vehicle to a standstill. Later iterations of the system on cars equipped with Automatic Cruise Control system are improved by combining radar and camera detection during fog, rain, and other situations where normal camera operations may be compromised.


AEB for Ford:

Collision Warning with Brake Support on the 2009 Lincoln MKS.

In 2009 Ford introduced the Collision Warning with Brake Support on the Lincoln MKS and MKT and the Ford Taurus. This system provides a warning through a Head Up Display that visually resembles brake lamps. If the driver does not react, the system pre-charges the brakes and increases the brake assist sensitivity to maximize driver braking performance.


AEB for Honda:

2003: Honda introduced an autonomous braking (Collision Mitigation Brake System CMBS, originally CMS) front collision avoidance system on the Inspire and later in Acura, using a radar-based system to monitor the situation ahead and provide brake assistance if the driver reacts with insufficient force on the brake pedal after a warning in the instrument cluster and a tightening of the seat belts lessen the severity of the predicted crash.

AEB for Mercedes-Benz:

2002: Mercedes’ “Pre-Safe” system was exhibited at the Paris Motor Show on the 2003 S-Class. Using electronic stability control sensors to measure steering angle, vehicle yaw, and lateral acceleration and brake assist (BAS) sensors to detect emergency braking, the system can tighten the seat belts, adjust seat positions including rear seats (if installed), raise folded rear headrests (if installed), and close the sunroof if it detects a possible collision (including rollover). A later version of the Pre-Safe system was supplemented by an additional function that can close any open windows if necessary.

2006: Mercedes-Benz’s “Brake Assist BAS Plus” was their first forward warning collision system introduced on the W221 S-Class, incorporates the autonomous cruise control system and adds a radar-based collision warning. 2006: the “Pre-Safe Brake” on the CL-Class C216 was their first to offer partial autonomous braking (40%, or up to 0.4g deceleration) if the driver does not react to the BAS Plus warnings and the system detects a severe danger of an accident.

2009: Mercedes introduced the first Pre-Safe Brake with full (100%) autonomous braking with maximum braking force approximately 0.6 seconds before impact, on the Mercedes-Benz E-Class (W212).

2013: Mercedes updated Pre-Safe on the W222 S-Class as plus with cross-traffic assist. Pre-Safe with pedestrian detection and City Brake function is a combination of stereo camera and radar sensors to detect pedestrians in front of the vehicle. Visual and acoustic warnings are triggered when a hazard is spotted. If the driver then reacts by braking, the braking power will be boosted as the situation requires, up to a full brake application. Should the driver fail to react, Pre-Safe Brake triggers autonomous vehicle braking. Pedestrian detection is active up to about 72 km/h (45 mph) , and is able to reduce collisions with pedestrians autonomously from an initial speed of up to 50 km/h (31 mph).


AEB for Nissan:

Nissan’s Infiniti brand offers both laser-based and radar-based systems. Brake assist with preview function anticipates the need to apply emergency braking and pre-pressurize the brake system to help improve brake response. Intelligent brake assist (IBA) with forward emergency braking (FEB) (on QX80) uses radar to monitor approaching speed to the vehicle ahead, helping detect an imminent collision. It provides a two-stage warning to alert the driver, and if the driver takes no action, the system automatically engages the brakes to mitigate collision speed and impact. Predictive forward collision warning system warns the driver of risks that may be obscured from the driver’s view. It senses the relative velocity and distance of a vehicle directly ahead, as well as a vehicle travelling in front of the preceding one. The forward emergency braking system judges that deceleration is required, it alerts the driver using both a screen display and sound, then generates a force that pushes the accelerator pedal up and applies partial braking to assist the driver in slowing the vehicle down. When the system judges that there is the possibility of a collision, it will automatically apply harder braking to help avoid one.


AEB for Subaru:

Subaru’s system, branded “EyeSight”, was announced in May 2008 using stereo camera technology to detect pedestrians and bicyclists.

2012: Higher Speed A-PCS on the Lexus LS enables deceleration from up to 37 mph (60 km/h), compared to the previous of 25 mph (40 km/h). This higher speed A-PCS uses the same technologies as the current A-PCS. This system increases the braking force up to twice that applied by average drivers. It is not available in U.S. markets. 2013: Pre-collision system with pedestrian-avoidance steer assist and steering bypass assistcan help prevent collisions in cases where automatic braking alone is not sufficient, such as when the vehicle is travelling too fast or a pedestrian suddenly steps into the vehicle’s path. An on-board sensor detects pedestrians and issues a visual alert on the dashboard immediately in front of the driver if the system determines that there is a risk of collision. If the likelihood of a collision increases, the system issues an audio and visual alarm to encourage the driver to take evasive action, and the increased pre-collision braking force and automatic braking functions are activated. If the system determines that a collision cannot be avoided by braking alone and there is sufficient room for avoidance, steer assist is activated to steer the vehicle away from the pedestrian.2016: Toyota announced it would make Toyota safety sense and Lexus safety system+ standard on nearly all Japan, Europe, and US models by the end of 2017.


AEB for Volvo:

Volvo City Safety multiple camera

2006: Volvo’s “Collision Warning with Auto Brake”, developed in cooperation with Mobileye, was introduced on the 2007 S80. This system is powered by a radar/camera sensor fusion and provides a warning through a head up display that visually resembles brake lamps. If the driver does not react, the system pre-charges the brakes and increases the brake assist sensitivity to maximize driver braking performance. Later versions will automatically apply the brakes to minimize pedestrian impacts. In some models of Volvos, the automatic braking system can be manually turned off. The V40 also included the first pedestrian airbag, when it was introduced in 2012.

2013: Volvo introduced the first cyclist detection system. All Volvo automobiles now come standard with a lidar laser sensor that monitors the front of the roadway, and if a potential collision is detected, the safety belts will retract to reduce excess slack. Volvo now includes this safety device as an optional in FH series trucks. 2015: “IntelliSafe” with auto brake at intersection. The Volvo XC90 features automatic braking if the driver turns in front of an oncoming car. This is a common scenario at busy city crossings as well as on highways, where the speed limits are higher.


Thanks to Wikipedia for this info!


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Cover Image Credit: Wards Auto


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