What is an Autonomous Emergency Braking (AEB) System?

At-work road safety

What is an Autonomous Emergency Braking (AEB) System?


AEB (Autonomous Emergency Braking) is a car safety feature that can save lives. As its name suggests, this technology automatically steps in to prevent a crash from occurring. When choosing a new car, it’s a really good piece of kit to have, especially if you do a lot of driving or drive for work.

Costs of AEB

Unlike a lot of advanced car technology, AEB systems actually don’t cost manufacturers much money at all. In fact, it costs as little as £40! This is one reason why AEB (Autonomous Emergency Braking) is becoming much more common on new cars. Safety experts in the know say that Autonomous Emergency Braking is among the road safety advances that could have the same impact as the seat belt did all those years ago.

Every new car is tested by Euro NCAP to see if it has AEB and if it does, it tests how sophisticated the AEB system is as a part of this assessment. The organisation says that when vehicles perform well in the tests, they are much more likely to prevent life-changing illnesses and needless deaths on our roads.

Experts also believe that AEB could have a bigger road safety impact than ESC (Electronic Stability Control) systems. Electronic Stability Control systems help to prevent crashes that occur when a driver loses control (rather than in a two or more vehicle crash). A quarter of all crashes are front to rear crashes, which AEB helps considerably. If it doesn’t prevent the crash altogether, it will certainly help to reduce the incident’s severity.

How does Autonomous Emergency Braking work?

The most basic of Autonomous Emergency Braking systems function at lower speeds with the view to preventing or reducing the severity of minor collisions in urban environments. The more sophisticated systems out there, function well across a wide range of speeds and so they can be useful in protecting against accidents where there is a higher potential of life-changing and serious injuries or deaths.

The best systems according to Euro NCAP tests (the tests produced a point-based score) can event detect pedestrians and cyclists as well as other cars.

However sophisticated an AEB system is, it will use sensors on the vehicle that detect obstacles and detect how likely a collision is. The device will usually begin with a warning to the driver that a collision could occur and alert the driver to brake using an alarm or warning lights on the dashboard. If, however, a driver doesn’t take action, the system with then automatically apply the brakes.

AEB systems take cruise control technology and apply it to improve the safety of vehicles. One of the first manufacturers to use this technology was Volvo in 2008 when it launched the XC60 SUV model with its City Safety system. The name of this system shows how technology was created initially to help low speed driving in urban locations. Volvo’s City Safety system operated from between 2 and 19 mph and it was designed to take action if the speed between two vehicles was less than 9 mph. If the speed difference was greater than 9 mph, the system would still work to reduce the severity of the collision but it wouldn’t be able to prevent it altogether.

The system aimed to help to prevent minor injuries and whiplash rather than be a life-saving system for high-speed collisions.

The system proved to be a success and when compared to similar SUVs that didn’t have AEB, the XC60 has 23% fewer crashes.

Improved Technology

Since 2008, technology has improved a great deal. Volvo’s City Safety system operated using a light detection and ranging (LIDAR) sensor. Nowadays, AEB technology uses cameras, radar or both to manage high-speed braking with much more sophistication.

The AEB software has improved massively and car manufacturers have much more confidence in these systems. The Autonomous Emergency Braking systems are much smarter and also brake harder than the original designs did over a decade ago. Early AEB devices offered brake forces of between 0.5G and 0.6G whereas modern devives deliver 1G.

Why should people choose AEB on their next vehicles?

One simple reason is that the technology works. A study in the US compared how effective Autonomous Emergency Braking systems were against other collision avoidance and driver assistance technologies. When vehicles were fitted with an AEB system, claims on car insurance to repair crash damage were lower in cost by between 10 and 14%.

Secondly, the University of Adelaide in Australia looked into data on 104 crashes and simulated how the use of Autonomous Emergency Braking technology could have reduced the speeds of the collisions and the injury risks. The research concluded that Autonomous Emergency Braking could reduce the number of fatal collisions by between 20 and 25 per cent. What’s more, crashes where injuries were sustained could have seen a reduction of between 25 and 35%.