If you were asked why there are speed limits in California, would you say that it's to reduce the amount of accidents that happen? If so, this is a common misconception.
Most people don't wear any safety gear while they drive. These same people may be very adamant about wearing helmets while biking or skateboarding, but they would never wear one in a car. Instead, they trust that the car's design -- the crash impact zones, seat belts, and other safety features -- will protect them.