In the past 20 years, newly produced automobiles have been equipped with occupant restraint systems, such as air bags, to reduce passenger injuries and fatalities in the event of a crash. An air bag is a passive restraint system—an automatic safety system that requires no action by the occupant. Government regulations, industrial participation, and social consciousness of safety have popularized the use of occupant restraints in vehicles worldwide. Using advanced technologies, additional restraints and enhanced functionalities are being implemented.