Roof CrushAuthor / Coordinator:
Auto Industry Lies and Recalcitrance Crush Car and SUV Owners in Rollover Crashes
The current roof crush standard became effective in 1973, and has only been revised since that time for extension to vehicles with a gross vehicle weight (GVW) of 6,000 pounds or less and to apply to vehicles with raised roofs. This weight limit has allowed manufacturers to increase the weight of SUVs over 6,000 pounds to evade the standard. The weight limit should be raised by NHTSA to 10,000 pounds.
The current standard requires a static test, in which the platen on the vehicle roof corner, above the A pillar, must bear 1 and a half times the vehicle’s weight with the windshield intact. In 1994, the agency, relying in part on obsolete data from the late 1980s regarding the number of sports utility vehicles (SUVs) in the vehicle population, terminated work on a rollover propensity standard by promising that a series of improvements in rollover crashworthiness and consumer information were forthcoming.
These promised improvements included advanced window glazing to prevent ejections and incentives to increase the use of seat belts. The agency also promised stronger roofs and has made additional promises in subsequent public statements about requiring improvements in door latches and hinges and upper side impact protection.
None of the promised regulations on rollover crashworthiness have been issued. This record is particularly shocking when we consider that the number of rollover-prone SUVs being driven by the general public has skyrocketed since 1994, and that light truck vehicles (LTVs) now comprise more than one-half of all new vehicle sales.
In order to "beat" the standard in recent years, manufacturers have taken the short cut of merely improving the bonding of the windshield to the vehicle structure, which helps the vehicle pass NHTSA’s weak test without helping occupants, because in a crash the windshield is typically gone by the end of the first quarter-turn. Once the windshield is gone, typically one-third of the roof strength disappears with it and the roof crushes.
When roofs crush in a rollover, the survival space for occupants is greatly limited or eliminated altogether, so that the heads and spines of occupants contact the roof. In addition, roof crush can open ejection portals– making windows and the windshield area very large and leading to ejection of occupants, which is frequently fatal. Don Friedman and Carl Nash, based on their years of crash investigations, have estimated that as many as one-half of seriously injured ejected occupants could have received their initial injuries as a consequence of roof crush.
The auto industry has tried to obscure the engineering principles which would have emphasized maintaining survival space by arguing in court and to NHTSA that occupants "dive" into the roof. This ignores the obvious fact that if the seat structures and safety belts held occupants in place during a roll, and if the roof was strong enough to withstand the weight of the car, the head and spine of occupants would be safe. In addition, safety engineer and attorney Don Slavik has shown through accident investigations that injuries among occupants directly correlates with the location of roof intrusion in the vehicle. That is to say, where there is roof crush, occupants are injured, and where someone is uninjured, there is little-or-no roof crush.
The current static standard, by testing only one side of the vehicle, does not provide any indication of what will happen in a roll when the following side, rather than the leading side, impacts the ground. Because in a real-world rollover the roof is already weakened by the first impact, roofs should be tested under those conditions. What is needed is a dynamic test that will provide the basis for a minimum roof strength standard.
The cost of improving roof strength is minimal, estimated by experts to be well under $50 per vehicle and to require less than 50 lbs. of strengthening materials. New lightweight steel alloys, just announced as marketable this spring, will make these figures even lower in mass production.
The issue of roof crush in rollovers was not addressed in the Transportation Recall Enhancement, Accountability and Documentation (TREAD) Act. Roof crush is a crashworthiness issue; the agency issued a "request for comments" last fall, and both the
Alliance of Automobile Manufacturers and Public Citizen submitted comments to the agency’s docket.
Given the survivability of these crashes and the availability of lifesaving and limbsaving technology, NHTSA should have a goal of bringing the fatalities from rollover and roof crush to virtually zero, with the ultimate aim of achieving the same level of protection from injury and death for the public as is now enjoyed by professional race car drivers.