A survey of accident statistics and harm to the head and neck from side impact and rollovers, suggests that vehicle upper structure should be the next high priority goal in reducing severe casualties. Contrary to contentions that roof strength has little influence on these injuries, these results from a multiplicity of studies, indicate that: (1) roof collapse should be eliminated, (2) passive interior padding improved, (3) laminated and retained glazing be installed, and (4) restraints improved by pretensioning retractors. A statistical analysis of the 1982 and 1983 National Accident Sampling System (NASS) files of rollover accidents, indicates a greatly increased risk of severe injury to occupants under a collapsing roof section. The increased risk was also demonstrated by: detailed investigation and analysis of 15 rollover accidents using protocol reported in the 1989 Society of Automotive Engineers (SAE) "Live Subject Safety Research Side Impact" paper. The instrumented data from sixteen nearly identical, rollover tests conducted by General Motors using conventional and rollcaged roofs, and unrestrained and belted Hybrid III dummies were analyzed. These data confirmed the increased risk. Limiting the deformation extent of vehicle roofs by lightweight structural changes, and simple and inexpensive force limiting, energy absorbing interior surface modifications, were demonstrated to reduce the risk of severe injuries by a factor of at least four.
Samenvatting