Science has helped reduce car accidents mostly through improvements in the design and engineering of automobiles. For example, the development of the seat belt alone in the 1960's has saved countless lives over the decades. Airbags in the 1990's have also saved numerous lives. Car frames now are designed with "crumple zones" in the front of the car to absorb more of the impact of a head on collision and not transfer that impact energy to the driver or passengers. But the science of not only cars themselves but also of various components affects safety. Tires, for example, have been improved over the years to better grip the road during wet driving conditions and prevent hydroplaning (the sliding of tires over a thin pool of water).
An interesting example was the phenomina of highway hipnosys. a while ago people where getting into wrecks seemingly for no reason. But some researches looked at the problem and realized it was due the the indeviduals not having stimuls and zoning out. As a result many raods around the world have been changed to prevent this effect.