In response to the National Highway Traffic Safety Administration (NHTSA) Authorization Act of 1991 and ongoing research into rollover and ejection mitigation, NHTSA initiated a research program concerning occupant protection in motor vehicle rollover crashes. NHTSA is addressing this occupant protection issue from two perspectives–preventing a rollover from occurring and protecting vehicle occupants during a rollover, including reducing the likelihood of ejections.

    Almost 60 percent of rollover fatalities occur in the 10 percent of rollovers involving either complete or partial ejection of vehicle occupants. Occupant ejections occur either through structural failures, such as door openings, or through window openings.

    NHTSA is evaluating the potential of improved door latches, side head air bags, and advanced glazing systems (an automotive industry term for transparent openings) to reduce occupant ejection. This report evaluates the progress of advanced glazing research since NHTSA issued its November 1995 report on occupant protection research to mitigate ejection through window openings.

    Each year on average about 7,300 people are killed and 7,800 people are seriously injured because of partial or complete ejection through glazing. Of the fatalities, more than 4,400 are associated with vehicle rollovers and the majority of these rollover victims were not using safety belts. In fact, 98 percent of occupants completely ejected and killed during rollover crashes were unbelted.

    Advanced glazing systems could save between 500 and 1,300 lives per year. These estimates assume a national safety belt use rate of about 66 percent (the average between 1992 and 1996) and a 20 to 51 percent range of effectiveness for advanced glazing systems in preventing ejection. Higher safety belt use rates directly reduce the estimated benefits of advanced glazing systems. As of the end of 1998, the U.S. national average seat belt use rate was 70 percent.

    In conjunction with Pilkington/Libbey-Owens-Ford, four types of advanced glazings were identified for evaluation in this research program. These were a non-HPR trilaminate, an HPR trilaminate, a bilaminate, and a polycarbonate (rigid plastic). The General Motors C/K Pickup side door window was selected as the platform for this work, since the production version already included encapsulated vertical edges.

The complete 1999 Report is available for viewing / printing in Adobe Acrobat format (543kb). Click Here to Download.

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source: NHTSA Files