“Braking bad... An explanation of the modern day emergency braking system. ”

​Ah, the morning commute. You're tired, running late and the traffic is crawling. Your phone is already chirping away with e-mails, appointment reminders and to-do lists that you'd rather not do at all. You glance down to see what the stupid phone is freaking out about, and when you look back up, the Range Rover in front of you has stopped. It's now inches in front of you. You make a face like surprised little Macaulay Culkin in "Home Alone" and jam on the brakes, hopefully in time to avoid an insurance claim and then…. Your emergency braking system kicks in before you have time to even think about pressing the brake.

So what is emergency braking and where do we find it? The good news is that these accident avoidance technologies have been available for years now and since testing and working on the first system with Volvo back in the mid naughties, I’ve seen vast improvements to a technology that was brilliant from the outset.

Automatic or Emergency braking does exactly what is says on the tin. The car automatically brakes in an emergency. These sophisticated systems use sensors and computers in your car to anticipate an accident and help you avoid that fender bender…. or worse. From recollection, when testing the original Volvo XC60, the car would completely miss the vehicle in front at speeds below 40kph (around 25mph) and greatly reduce the impact at higher speeds meaning what would have been a amor incident ended up looking (and feeling) like a fender bender. 
Every manufacturer uses a different setup, so I’ll use Volvo (called City Safety) and Subaru’s systems (called EyeSight) as examples.

Subaru's EyeSight uses two black and white cameras that work like your eyes to triangulate the speed and distance of the vehicle in front of you. They're mounted at the top of the windshield, and they scan every 0.1 seconds, looking for contrast with the background and vertical surfaces. The software is programmed to recognise several types of images, like the rear ends of vehicles, motorcycles, bicycles and pedestrians.

Volvo uses lidar which is a laser radar. The system sends out a signal that pings off objects in front of it to determine distance and speed. Since lidar works best at short range, Volvo also has a camera mounted in the windshield and radar in the bumper that work together at high speeds as part of its collision warning system with full braking capability. The radar can see several hundred yards in front of the car, but it can't tell what it's seeing. The camera picks up on what the radar is seeing and can identify the object as a problem or something to ignore.

So far, this is just how your car knows that there's a vehicle in front of you, and that the vehicle has slammed on its brakes. At this point your car's computer does some clever calculations and determines that you're about to hit the vehicle in front. It can also sense that you're not doing a thing about it. It's time for your car to take things into its own hands.

“At under 20 miles per hour (32.2 kilometers per hour) or so, most systems can avoid a crash completely, although the goal is merely to minimize the impact and therefore the injury. “
Fact: Most people don't press the brakes hard enough when they're trying to avoid a crash.
The Volvo system is actually two systems layered one on top of the other: City Safety for slower speeds, and the collision warning system for higher speeds. Since in our example you're crawling along on your way to work, City Safety will come into play. If the lidar thinks you're too close to the car in front and you're not doing anything about it, you get no warning. It starts braking for you, and then lights up a red LED in the windshield that mimics a brake light to get your attention. The idea is that maybe then you'll react and press the brake on your own; but if you don't, Volvo's got it.

If you're going a bit quicker, Volvo's second system will pick up where City Safety leaves off. Above 30 miles per hour (48.3 kilometers per hour) or so, the system will give you a warning if you're following too closely. It will also precharge the brakes so they're ready to slow you down as soon as you heed the warning -- or take over if you don’t.
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Automatic braking doesn't operate alone. They are part of more comprehensive systems that includes throttle management, lane departure warning, adaptive cruise control and other safety systems. And the technology is only getting better, with improved cameras and sensors. As the technology moves forward (EyeSight and City Safety are both already on their third generation), it'll get cheaper, and as it gets cheaper, it'll be in more cars, which benefits everyone.
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If you have any questions, feel free to join in the discussion on our Facebook group Miss Auto Know