Automatic emergency braking might seem like a rather up-to-date and modern invention, but the truth is that the first autonomous emergency braking system for cars was detailed by George Rashid in 1954! Rashid’s invention was developed with some success with the help of Paul Dudeck, but was not put into large-scale development over concerns of consistency and liability. 

In 2006, however, Mercedes launched the Brake Distronic Plus system which used long and short-range radar to bring the car to a full stop when faced with collision, even if the river does not touch the brakes! These systems are now quickly advancing and extending beyond the bounds of luxury vehicles.

cars on road viewed from above

What is automatic braking?

To put it simply, an autonomous emergency braking system is a technological advancement which uses long and short-range radar to detect hazards and prevent collisions. 

By and large, they have been successful in reducing avoidable collisions; research completed by the Society of Motor Manufacturers and Traders (or SMMT) found that since 2012, 66.8% of new cars have come with one or more self-activating safety systems as a standard. In this time, road accidents in the UK have fallen by nearly 10%, partly as a result of these innovations.

How does automatic braking work?

Different manufacturers have their own particular systems, of course, because of the way in which an automatic car braking system has to relate to the rest of the vehicle. As a result, no two systems work  in exactly the same manner; however there are some basic principles which carry across all systems.

These are some of the biggest, leading manufacturers of vehicles with automatic braking:





General Motors



Jaguar Land Rover





Mitsubishi Motors




Tesla Motors



Volvo Car USA

First and foremost, every system will have some kind of sensor which records the distance between the vehicle and objects in front of it (usually other cars). This sensor will automatically monitor the space in front of the car, and is connected to the brakes.

Secondly, the automatic braking system will function in one of two ways: preemptively or reactively.


Pre-emptive automatic braking systems, or collision avoidance systems, seek to directly avoid crashes by removing control from the driver in emergency situations. This means that once the sensors are triggered by a hazard they will engage the brakes automatically, without giving you time to react and without warning. As a result, these systems are more effective at preventing collisions altogether, but many drivers do fear the lack of control that is left to them.


Reactive automatic braking systems, or collision mitigation systems, seek to prevent collisions by first making the driver aware of hazards and only removing control once a collision becomes imminent. As such, they will warn you as something approaches your car. Only once an object crosses a predetermined threshold will the brakes be engaged. This gives you, as the driver, forewarning and time to make a decision, which is why many people prefer them.

In either case, once the required conditions for automatic braking are met, an automatic car braking system will trigger a technological response which engages the brakes of your car.

truck stopping with AEB

Applications and limitations

So, to make it simple, automatic emergency braking systems (or AEBs) are primarily used to reduce the chances of a collision and prevent accidents. They do this by automatically engaging a vehicle’s braking system when their sensors pick up an object within a certain distance of the vehicle. They do have their limitations, however.

First and foremost, some AEB systems do not work below a certain speed. This is quite low, usually around 5 mph, but it means that they aren’t generally effective against minor parking incidents or dings in slow moving traffic. Other AEB systems will also not work above a certain speed, sometimes as low as 15 or 20 mph. In these cases, the systems are designed to prevent minor crashes in urban areas, but some work up to speeds of 155 mph and are intended to mitigate more serious accidents.

However, AEB systems do have other uses. For example, they are being adapted for use in hazardous weather conditions such as snow. Most notably they are being applied to improve friction control, thereby lowering the chances that a driver will lose control of the car in snowy conditions. These technological advancements are still relatively new, but a recent study found that they are already having an effect on the confidence of drivers facing adverse weather.

In fact, this confidence and perceived security was understood by researchers to be almost as influential as the technology itself because it allowed drivers to plan and react in a more measured and assured manner.

Automatic braking and car tyres

Of course, all types of breaks - whether operated by human or automatic input - still need to work with your car tyres. As such, tyres that are in a good condition will be able to stop the car faster. The same can also be said about the road conditions. Aquaplaning and other dangers, such as snow or ice, can all further reduce the effectiveness of any type of braking, so good tyres are a must.

car driving in snow

Put it this way: automatic braking systems work with your brake discs and callipers. They are not able to work around your choice of tyres. As such, it is always worth checking that your tyres are above the minimum tyre tread depth. In the UK, the tyre tread legal limit is 1.6 mm or more but, when it comes to winter tyres, you should consider getting new tyres earlier which allow safer braking.

Automatic Braking Systems Protect Road Users!

So, to sum it up, AEB systems protect drivers and road users by automatically engaging a car's brakes when a hazard is recognized. While this technology is still advancing, there are signs that it will soon be adapted to improve safety and prevent collisions in even the most challenging of situations. As a driver, you should always be vigilant on the road and you should be sure to keep your front and rear brakes in good condition, as well as having summer tyres and winter tyres with a strong snow grip.