Window Glazing

By Julio M. Zapata

Are auto manufacturers doing enough to reduce occupant ejection and produce safer vehicles?

A properly designed vehicle should provide a stable Occupant Survival Space such that the roof does not cave in and the windows of the vehicle do not shatter out creating openings for occupants to fly through and out of the vehicle. The glass in an automobile should protect drivers and passengers alike. Windows and windshields can and should help prevent occupant ejection in automobile crashes. Moreover, many manufacturers rely on window glazing to help support the roof and sides of a vehicle. Unfortunately, and to the detriment of the auto consumer, window glazing in autos today does not actually afford these basic protections, despite the availability of tested and feasible solutions.

What is Window Glazing?

Federal regulations allow three types of glass for use in automobiles—tempered glass, glass-plastic, and laminated glass.

Automakers began using laminated safety glass for automobile windshields in 1927, but over the years discontinued using it or limited its use to windshields only. To make laminated safety glass, the manufacturer sandwiches a thin layer of flexible clear plastic film called polyvinyl butyral (“PVB”) between two or more pieces of glass. This plastic film holds the glass in place when the glass breaks, helping to prevent injuries from flying glass. Thus, laminated safety glass helps hold occupants within the Occupant Survival Space during a crash.

Glass-plastic consists of either laminated or tempered glass with a clear “plastic” laminate on the inside of the glass that faces the occupants. The benefits are obvious: the inner-layer plastic not only protects against flying glass, it also helps hold the glass together, thus helping prevent ejection and retain the structural support features afforded by the glazing.

In contrast, tempered glass is a single piece of glass that is made by a process that heats, then quickly cools the glass, to harden it. The tempering process increases the strength of the glass. When tempered glass is struck, it does not break into sharp, jagged pieces as normal window panes or mirrors do. Instead, it breaks into little pebble-like pieces. The tempered glass used in autos is slightly less expensive than laminated safety glass.

What is the problem?

Auto manufacturers have known for over 50 years that tempered glass is inferior. In 1957, Dupont Research conducted tests on more than 500 examples and concluded that “just as tempered glass offers practically no resistance to flying missiles once it is broken, it is completely ineffective in retaining a passenger in a car if the [glass] is cracked in an accident situation. This is in sharp contrast to laminated glass which retains great penetration resistance after shattering and will very effectively retain a passenger inside the car. Since accident studies show much greater likelihood of serious injury to a passenger thrown from a car, this characteristic of tempered glass is a serious shortcoming.”

In 1998, the National Center for Statistics and Analysis (“NCSA”) stated that more than 60,000 passenger vehicle occupants were completely or partially ejected when windshields, side windows, rear windows and roof windows did not retain the occupants in a collision. In fact, more than fifty percent were hurled through the side windows. Despite this data, auto manufacturers continue to gloss over known risks posed by deficient window glazing in their automobiles.

The National Highway Traffic Safety Administration sets minimum standards, which automobile manufacturers are free to exceed. When it comes to installing safer windows in their vehicles, however, auto manufacturers have failed to do so. This is despite the stated purposes of the minimum standard FMVSS 205: to reduce injuries resulting from impact to glazing surfaces; to ensure a necessary degree of transparency in motor vehicle windows for driver visibility; and to minimize the possibility of occupants being thrown from the vehicle windows in collisions.

How are glazing cases handled?

Cases involving defective vehicle products, including side window defects, require the application of strict liability laws. Strict liability laws require the victim of an accident involving a defective product to prove that the product was defective and unreasonably dangerous at the time it left the defendant’s control, and that the defect was a cause of the plaintiff’s injury. Unlike plaintiffs in other tort cases, the plaintiffs in a defective product case do not need to prove negligence in order to recover compensation from the auto manufacturer and/or their insurance companies. Product liability lawsuits may be filed on grounds of design flaws, manufacturer’s flaws, insufficient warning labels or directions, and other causes.

It is obvious that the federal minimum standards are not sufficient to persuade auto manufacturers to create safer vehicles. The only pressure on auto makers to use safer glass comes from auto safety lawyers who sue auto makers when their vehicle glazing harms drivers and occupants in crashes, rather than protects them.