Back in the day, the parking brake was known as the emergency brake. I grew up thinking that if you really needed to stop, you cranked that handle up to get the car stopped. After driving for a few years, I realized that locking up the wheels is the best way to lose control of the car, which is why we have anti-lock brakes. The challenge in preventing accidents with other cars and pedestrians is not only to get the brakes activated more quickly, but also to get the brakes themselves to function better.
It doesn’t matter how fast the automated systems inside the car activate the brakes to avoid a collision if the brakes themselves are incapable of stopping the car in time. This is where the Autoliv emergency brake comes in. This device is a metal plate that hides under the car.
It’s able to extend and come into contact with the pavement in a fraction of a second and uses vacuum to establish a massive amount of stopping force. The system can exert 15,000 netwons of force and the maker claims it can shorten braking distances by as much as 40%.
I can only imagine that the G forces inside the car when using this brake system would be considerable. Autoliv says that the braking system would work only at speeds below 40 mph. Presumably that would be to prevent any sort of injury to occupants of the vehicle that might be caused from rapid stops from higher speeds.