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December 15, 2005
FORMER NHTSA OFFICIAL DECRIES ROOF CRUSH PROPOSAL
A former NHTSA senior official and highly regarded crashworthiness engineer has warned the agency that its proposed amendments to the federal roof crush standard, FMVSS 216, are “a license to reduce the durability of the roof to withstand multiple impacts” and will “increase rather than decrease the rollover casualties that can be attributed to roof intrusion.” Dr. Kennerly Digges based his conclusions on independent tests recently carried out under his direction at George Washington University with the support of the Santos Family Foundation, as well as on earlier research.
Digges enumerated the proposal’s problems, including the following:
--A single static roof test of a pristine vehicle, which is called for by the proposal and the present standard, “does not adequately represent the rollover crash conditions that cause roof collapse in the field.”
--“…lateral shifts in roof deformation can play a role in exposing belted occupants to partial ejection. The proposed FMVSS 216 does not address the roof and ground contact injuries that are associated with more hazardous deformation modes than that produced by the specified static test.”
-- Occupant modeling carried out during the GWU test program “indicates that lateral shifts in roof deformation can play a role in exposing belted occupants to partial ejection.
The proposed FMVSS 216 does not address the roof and ground contact injuries that are associated with more hazardous deformation modes than that produced by the specified static test.”
--Analysis of FMVSS 216 test results “suggest that the current version of FMVSS 216 is deficient in that it does not assure the durability of the roof structure to withstand the varied and repeated roof loading that takes place in real world rollovers.” The data “also indicates that the FMVSS 216 upgrade does not adequately address this deficiency. At least one of the vehicles tested passed the requirements of the new standard, but had a residual strength after glass breakage that was among the lowest of all vehicles tested.”
--If the proposed standard preempted rules of tort law, as NHTSA has indicated, “…such action would free manufacturers to reduce weight and cost by designing so that the glass supports an increasing fraction of the 250% load requirement. There would be no sanctions to prevent the design of a roof that totally collapses after the glass breaks. As a consequence, the durability of the roof to withstand multiple impacts would decrease. The standard would be counterproductive – increasing the injuries to belted occupants in rollovers who are subjected to multiple roof impacts.”
Click here to see the full text of the comments. For background information and links concerning NHTSA’s proposed rulemaking, visit roof-crush articles in the Current Developments archives at left.
Posted by MVHAP at December 15, 2005 06:22 PM