External Airbags


They could help cushion a car, and protect pedestrians, in a collision


Volvo and other automakers, plus automotive suppliers such as TRW



For decades, inflatable airbags have been protecting people in cars from the devastating jolt of collisions. There are airbags mounted in the dash, steering wheel, side panels, seats and even seat belts.

Despite their varied locations, these airbags all have one thing in common: They’re inside the vehicle. But what if someone made airbags that inflated on the outside to help protect the car — and pedestrians — before the moment of impact?

TRW Automotive, a maker of safety technologies, is developing a large airbag that would fit into rocker panels on the side of the vehicle, on the beam below the doors. A system of cameras and radar on the car would detect when a collision was imminent and send a signal to the airbag, which would inflate outward and upward within 30 milliseconds.

In this way, the side airbag would absorb some of the energy of the collision before the vehicle’s frame was struck.

Crash tests have shown that the external airbags can reduce the impact on a vehicle’s interior – the inward crumpling of a car’s frame and doors – by up to 35%, said Emiliano Core, who is developing the airbag system along with Lothar Zink and other TRW engineers. Collisions to the sides of vehicles, which offer less protection than the front or rear, account for about one-third of traffic fatalities in the U.S., he said.

The airbag system is still in the concept phase, and there’s no timetable for when it might be ready for mass production. But “we have at least one carmaker who is interested” in the technology, Core said.

Other external airbags also are in the works. TRW has developed an airbag that would deploy from the trailing edge of a vehicle’s hood, spread over the windshield and cushion the impact for pedestrians struck by cars. Volvo has installed similar airbags in its V40 hatchback sedan. And Mercedes-Benz has developed an airbag that inflates underneath a car and acts as an anchor by rubbing the road surface, slowing the vehicle down.

Of course, these airbags all are last-ditch safety features. Ideally, the sensors on today’s computerized cars would detect an obstacle or a pedestrian and apply the brakes to avoid a collision. But if they don’t, it’s good to know your car might someday offer another pillowy layer of protection.