What is Emergency Autonomous City Braking?

No matter how diligent a driver you are, every so often a situation might arise which you are unprepared to deal with.

These sorts of hazards occur more frequently in cities than in any other driving environment, where the potential for distractions and sudden dangers to arise with little or no time for the driver to react.

Even then, many drivers are unaware of the capability of their cars and don’t apply sufficient braking pressure in these split-second situations. That’s why many manufacturers have introduced what is known as Emergency City Braking to their latest models.

As with many of the most advanced systems fitted to our everyday cars, the first application of the system was in the 1990s version of the Mercedes S-Class – now, the system features in a variety of cars under various guises. Those employed by Volkswagen (City Emergency Brake), Ford (Active City Stop), Land Rover (Intelligent Emergency Braking) and Volvo (City Safety) all work to very similar principles. But how exactly do they work, and when should you expect them to intervene?

Land Rover’s City Braking system helped the Discovery Sport to a five-star Euro NCAP rating

The techy stuff

Autonomous Emergency Braking systems rely on several means of scanning the road ahead for potential hazards. These invariably use radar, stereo cameras and/or lidar – that’s laser scanning, to you and me. The data gathered from these systems is combined with the car’s speed and direction to calculate whether or not a collision with another car/pedestrian/obstacle is imminent.

If the system believes an impact is likely, the driver will be alerted, usually via an audible warning system and light on the dashboard. The system primes the brakes and anti-lock system to make them more sensitive when the driver applies them. If the driver doesn’t take the necessary action to avoid the danger, the system will then intervene.

Most versions are capable of applying full braking force, and in the case of a sudden hazard, can react far more quickly than a human is capable of doing. The end result won’t necessarily avoid a collision altogether (though in many instances it will) but at the very least will vastly reduce the severity of an accident.

Here’s a video from the German automobile standards authority, ADAC, showing various automatic braking systems in action:

Braking into the mainstream

Now you’re more clued-up about autonomous emergency braking why not learn about the other great bits of tech keeping you safe on the roads – lane keep assist, adaptive cruise control and anti-lock brakes. Then take a look at our deals page for the latest discounts, then take a look at our car configurator to see how much you could save on your next car.