Germans invent external airbags

Automotive safety expert ZF TRW has successfully built a new external side airbag that it says can reduce the force of a side collision by 30 per cent.

The prototype airbag, stowed in a car's sills beneath the doors, has a volume of more than 200 litres — twice the size of a conventional internal side curtain airbag.

Designed to deploy shortly before a side impact, the new external airbags could help future sports cars or city-cars that are small or sit low to the ground pass stricter side impact regulations.

They could also significantly cut both injuries and fatalities caused by 'T-bone’ style accidents common in places like North America.

Obstacles to overcome before the world’s first external side airbags are offered on production vehicles are the corrosive effect of rain, salt and dirt damage because of where the airbags are placed.

One huge engineering leap that needs to be made is developing a foolproof software to detect when to deploy the airbags. Unlike internal airbags, the side impact bags are only effective if they inflate before the impact.

Another safety device developed by ZF TRW is a pyrotechnic charge that pushes the driver or passenger seat away from the impact to make room for a large side airbag.

External airbags are nothing new. Airbags stored under the bonnet of Volvo's V40 deploy in a collision with a pedestrian to reduce injuries, but this is the first time large external airbags have been used to protect the occupants from an impact involving another vehicle.

Some industry commentators are predicting that with the introduction of autonomous driverless cars airbags will soon become unnecessary as cars will be almost incapable of crashing into each other, but that's likely to be at least a decade away.