External airbag could protect pedestrians and cyclists

The Scandinavian car company has integrated an airbag beneath the bonnet of its 2013 V40 vehicle, which goes into production in May.

Thomas Broberg, senior technical advisor at Volvo, told The Engineer: ‘We’re using airbag technology to have a cushioning effect on the outside of the vehicle to try and protect pedestrians.’

The external airbag, which was developed in Sweden at Volvo’s R&D facility, fully inflates in less than a second and is most effective in collisions involving cars travelling between 12mph and 31mph.

The airbag is deployed when sensors in the front bumper register any physical contact between the car and a pedestrian or a cyclist.

Upon impact, the rear end of the bonnet is released and elevated four inches by the deploying airbag, which inflates to cover the area under the raised bonnet, in addition to approximately one-third of the windscreen and the lower part of the steel pillars that support the windscreen.

‘Another reason for raising the bonnet is to create more space between the hood and the hard components in the engine-bay compartments — basically creating more space to provide a cushioning effect,’ said Broberg.

The concept of external airbags has been around for several years but taking the leap from concept to being put into production is significant, according to Broberg.

To complement the external airbag, Volvo has developed a collision-warning and auto-brake system, which reduces the speed of the vehicle if a collision is unavoidable and sounds an alarm to alert the driver.

The external airbag and the collision-warning system could have a significant impact on pedestrian and cyclist casualty rates. Statistics from the Department for Transport show that 5,605 pedestrians and 2,771 cyclists were killed or seriously injured on Britain’s roads in 2010, with most fatalities occuring in incidents where the car was travelling below 40mph.