For nearly three decades, automakers and regulators concentrated on how to make crashes more survivable. The result is even low-priced compact cars have as many as 10 air bags, full complements of three-point seat belts, and body structures designed to dissipate crash forces. Highway fatalities in the U.S. have fallen to the lowest level in six decades. NHTSA is looking for the next crash-avoidance technology that is ready to be pushed into all cars.