Airbags in cars are moving away from just protecting the occupants of the vehicle, for now the "braking bag" in Mercedes-Benz ESF 2009 S400 Hybrid experimental safety vehicle, will even ensure the safety of those outside the car and of the vehicle itself.
The braking bag is a specially designed airbag that lives on the underside of the vehicle, and deploys when the PRE-SAFE system determines that a collision is imminent.
Located just forward of the front axle, the braking bag provides friction to slow the vehicle even further and stabilises the car by providing more contact with the road.
The technology minimizes the car's "dive" as it brakes, which "improves geometrical compatibility with the other party in an accident," reports Carconnection.com
The Braking Bag is deployed just before the crash, supporting the car against the road surface by means of a friction coating.
The vehicle's vertical acceleration increases the friction, and has an additional braking effect before the impact.
The Braking Bag uses the PRE-CRASH sensors in Mercedes-Benz cars, which are already able to initiate preventive occupant protection measures in critical driving situations.
There are several advantages to this unusual auxiliary brake-firstly, the rate of deceleration is briefly increased to over 20 m/sec/sec, which scrubs additional energy beyond the potentials of a wheel brake, thereby reducing accident severity.
As the car is raised upwards by up to eight centimetres within a short time, the dive effect that occurs with conventional brakes is substantially compensated, which thus improves geometrical compatibility with the other party in an accident.
This vertical movement also improves the effects of the restraint systems- the seats move towards the occupants by around three centimetres, which enables the belt tensioners to take up more slack.
Downward support for the vehicle during the crash reduces the typical diving motion during a collision.
Thus, one can say that the braking airbag has the effect of an additional crumple zone.
Initial driving tests in a C-Class have already shown the effectiveness of this new auxiliary brake.
However, it will still take some time for the Braking Bag to become another component of the PRE-SAFE system.