According to the patent filing, "injury to the pedestrian is often caused not only by the initial impact of the vehicle and the pedestrian, but also by the ensuing, secondary impact between the pedestrian and the road surface or other object".
Often the pedestrian is hit by the bonnet of a vehicle and carried along for a while. Only once the pedestrian is brought up to the speed of the car does the driver react, usually slamming the brakes and bringing the car to a halt.
The pedestrian, though, continues at the car's old speed, only finally coming to rest when he or she hits another object, be it another car, street furniture, the ground or something else.
Google's patent aims to eliminate the secondary impact for pedestrians by having the entire front of the car, including the bonnet, front bumper and fenders, covered in a sticky adhesive that can, essentially, catch and hold the pedestrian.
Having a constantly exposed sticky surface is not optimal, though, as the adhesive would be catching dust, pollution and detritus regardless of whether the vehicle is stationary or on the move.
Instead, Google's solution includes a protective coating over the sticky layer. The protective layer breaks automatically upon impact with a pedestrian, adhering him or her to the car.
While the idea sounds good in theory, the company has yet to demonstrate that it works in the real world or, even, in closed trials. The search giant has yet to name which substances would act as the adhesive and the protective, but breakable, layer.