This is what will happen after you hit someone with your car.
The adhesive layer would coat the front of a self-driving car but be covered by something that's not sticky. When you hit someone, the outer layer would be removed, exposing the glue.
After a crash, the victim would be stuck to the front of the car, preventing them from another injury as they're thrown backwards.
The existence of a patent about gluing people to cars doesn't mean that it's actually going to happen, though. Large technology companies like Google patent lots of ideas, but only a few actually make it to production.
Self-driving cars are, in theory, safer than cars driven by humans. But they still get into accidents. In February one of Google's driverless cars hit a bus in Mountain View. And the owner of a Tesla Model S claimed earlier this month that his car crashed into a trailer while in "Summon" mode.