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The occupant retention performance of laminated and tempered side glazing during rollover collisions is analyzed. A brief history of automotive glazing is given, including a discussion of current technology. A summary of glazing failure mechanisms is provided, along with the results of impact and quasi-static pushout testing of undamaged commercial and prototype door windows. The investigation shows that supported laminated side glazing gives performance comparable to windshield glazing and can effect both primary and secondary containment of occupants. Results of documented unplanned rollover collisions and staged rollover tests are presented in support of the conclusions drawn.

The non-uniformity of temper of 27 motor vehicle door windows as measured by the polarization method is presented, illustrated by two photographs of windows between crossed polarizers. The tempered glass fracture characteristics of 11 Geo Prism door windows are illustrated by two video frames of the windows after fracturing by door deformation slowly applied at bumper level. The speed of some moderate sized fragments was measured to exceed 60 km/h, due to strain relief rather than contact by an intruding object. Glazing history is briefly summarized, with our support of the NHTSA conclusion that more than 1300 lives per year could be saved cost effectively by replacing tempered glass by an “advanced glazing.”

1990 Geo Prism front door side tempered glass windows 3 mm thick were slowly bent, or shock loaded, to failure, with the glass clusters and fragments then found as large as 13 x 10 cm, weight to 42 grams, with some sharp points and slivers, and speed of release from the glazing surface of intermediate size pieces to 23 km/h. The fracture patterns of the tempered glass bent or shock loaded to failure were often oblique rather than perpendicular, in comparison to the patterns of an unloaded tempered glass broken by a locally applied sharp pointed object. This explains the sharpness and many lacerations of tempered glass shattered in road crashes, often under conditions of bending or shock loading of the edges of the glazing before it fails. Modification of Federal Motor Vehicle Safety Standard 205 to include fragment studies and laceration effects are suggested.