Laminated Glass and Accident Safety: Can Auto Glass be too Safe?
December 4, 2012

by Casey Neeley,

A local report about consumer safety surrounding the use of laminated glass for sidelites which aired recently on NBC 6 South Florida asks the question: are vehicles becoming too safe?

In January 2011, the National Highway Traffic Safety Administration (NHTSA) released a final rule centering around the extended use of laminated glass as a safety precaution aimed at reducing the overall number of passenger ejections resulting from rollover accidents. The applicable standard, Federal Motor Vehicle Safety Standard (FMVSS) No. 226, "Ejection Mitigation," "applies to the side windows next to the first three rows of seats, and to a portion of the cargo area behind the first or second rows, in motor vehicles with a gross vehicle weight rating (GVWR) of 4,536 kilogram (kg) or less (10,000 pounds (lb) or less)," according to the standard.

In a statement issued on the rule, U.S. Transportation Secretary Ray LaHood said, "Safety is our highest priority. This new standard will help save lives and reduce injuries by requiring vehicles to have a safety system that keeps occupants in the vehicle in a rollover crash."

"Rollover crashes are the deadliest of all crash types and this is another important step in our efforts to reduce fatalities and serious injuries that result from them," said administrator David Strickland, National Highway Traffic Safety Administration in the 2011 statement. "When fully implemented, we believe this standard will prevent on average 373 fatalities and 476 serious injuries every year."

The NHTSA states in the standard that, "Once a rollover occurs, vehicle crashworthiness characteristics play a crucial role in protecting the occupants. According to agency data, occupants have a much better chance of surviving a crash if they are not ejected from their vehicles."

Analysis of data collected by NHTSA lead the agency to the conclusion that laminated glass in sidelites would significantly reduce the number of fatalities resulting from rollover crashes.

"Rollover crashes can be complex and unpredictable," reads FMVSS No. 226. "At this time there is no conventional rollover scenario or test representative of real-world rollover crashes that can be used in a dynamic test to the agency's satisfaction to evaluate the performance of ejection mitigation countermeasures. Yet, this final rule achieves ejection mitigation benefits notwithstanding the absence of a dynamic procedure. Agency research has found that full coverage of the side windows is a key element to mitigating ejection. This standard adopts a component test that assures there is full coverage of the side window to diminish the potential risk of the windows as ejection portals and that assesses ejection mitigation safety systems for as long in the crash event as the risk of ejection reasonably exists."

While the NBC 6 story focuses on the repercussions of installing laminated glass and the resulting potential increase in risk of drowning deaths, an article written for NHTSA and referenced by the Center for Auto Safety shows these claims may be unsubstantiated.

In his article, "Drowning Deaths in Motor Vehicle Traffic Accidents," Rory Austin states, "Very little is known about drowning deaths in the United States as the result of motor vehicle accidents." Though Austin concedes that drowning deaths are not closely studied and accurately reported enough to comment on the number of drowning deaths attributed to vehicle immersions, he does cite annual averages for immersed vehicles. In his article, Austin states that "immersion is not a good predictor of whether the occupant fatalities involved drowning," but cites annual average numbers of 203 drowning deaths resulting from 384 fatal accidents listing vehicle immersion in the reported sequence of events.

Comparatively, the Center for Auto Safety states in multiple reports that rollover accidents are responsible for an estimated 10,000 deaths annually.

Would the number of vehicle immersion drownings increase as the use of laminated glass in vehicles increases, ultimately decreasing the safety of the vehicle? Ben Kelley, auto glass safety consultant, says not necessarily.

"Overall, the safety community has been supportive of laminated glass in other than windshields, where it has long been required," says Kelley. "There are trade-offs, as the NBC Miami piece suggests, but on balance the negatives are outweighed by the positives."

Kelley goes on to offer alternatives to the way immersed vehicles are recovered and passengers are rescued as opposed to reducing the impact safety of the glass.

"Perhaps rescue personnel would want to look at developing better tools and techniques for punching through laminated glass in the situations described in the news piece," says Kelley. "It's not unlike early concerns about possible airbag disposal hazards in junked cars with undeployed airbags. The scrap industry was fearful of such hazards but eventually developed techniques and guidelines for handling them."

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