Usage patterns and misuse rates of automatic seat belts by system type.

This study examined seat belt usage in North Carolina by drivers of 4,151 late model cars equipped with a variety of restraint system types. We measured usage by restraint type (automatic belt, air bag, manual belt), by make/model and by driver characteristics (age, sex, and race). Usage ranged from a high of 94.2% for motorized shoulder belts (but with only 28.6% lap belt usage in these cars) to 73.9% usage of manual lap/shoulder belts in cars equipped with air bags. Various types of misuse of the shoulder belt (e.g. excessive slack, detachment from the door, placement under the arm) were observed in nearly 6% of the sample.