Waymo has received a U.S. patent for technology designed to make a self-driving vehicle’s surface less rigid after processors determine that a collision with a pedestrian is imminent, according to a document filed with the U.S. Patent and Trademark Office. 

The change in rigidity would theoretically reduce the force of impact, potentially saving the life of a pedestrian, bicyclist or animal. But Waymo, formerly known as the Google self-driving car project, has not publicly revealed its plans for such technology.

The system, according to the filing, might employ an arrangement of structural elements that would allow the easing of surface tension in such areas as the hood, bumper or a panel of the vehicle. One option is to use cables as such tension members so they could be cut, released or loosened just before impact. Another option is to use tension members incorporated into one or more pillars of the vehicle. After sensors detect and classify the object in the vehicle’s path, the tension members would respond accordingly.