Volvo's pedestrian airbag: how it works

Volvo is first manufacturer to offer a pedestrian airbag. The system was a world breakthrough when the all-new Volvo V40 was launched in Geneva earlier this year.

It works by seven sensors embedded in the front of the car which transmit signals to a control unit. When the car comes into contact with an object, the signals change. The control unit evaluates the signals and if it registers what it interprets as a human leg, the pedestrian airbag is deployed.

The airbag raises the bonnet to create distance, and cushions the impact around the hard parts of the area near the windscreen. In its inflated position, the airbag covers the entire windscreen wiper recess, about one-third of the windscreen and the lower part of the A-pillars. The entire sequence from activation of the system to full inflation, takes a few hundredths of a second.

The system is active at speeds between 20 and 50 km/h. The majority of accidents involving pedestrians happen at up to 40 km/h. In Europe, 14 percent of traffic fatalities are pedestrians. The most serious head injuries involving pedestrians and cars are caused by the hard structure under the bonnet panel, the windscreen's lower edge and the A-Pillars.

The technology was developed using computer simulations and human-like leg and head forms.