In 1984 Transport Canada, the Canadian Ministry equivalent to the United States Department of Transportation, conducted an extensive study of school bus safety which included a series of crash tests using new Type A, B, and C school buses. All buses were fully operational at the time of the tests with engines and fuel systems intact and operational. All buses were equipped with both belted and unbelted instrument equipped dummies. The buses were crashed into a massive stationary concrete barrier at a speed of 30 miles per hour.
Test results indicated that the lap belted dummies on the large Type C school bus (called Type I at that time) recorded head impacts two to three times more severe that the unbelted dummies. Lap belted dummies on the small Type A and B buses incurred forces three to five times higher than the unbelted dummies.
The crash test summary concluded that The results indicate that. in a frontal collision, belted school bus occupants are liable to suffer more serious injury than unbelted ones.
Furthermore, from the film data the belted dummies experienced more severe neck extension due to the angle at which they struck the seat ahead of them than did the unbelted ones. The extension of several restrained dummies was judged to be life threatening. Dummies restrained by seat belts in both of the small buses experienced HIC (Head Injury Criteria) values in excess of 1000, whereas the unrestrained dummies experienced HIC values of less than 1000.
The report further states that in the Type B and C buses (called Type II and III at the time) tested the restrained dummies' heads struck the seat backs in a manner that did not permit efficient energy absorption by those seat backs. Sharp peaks in head acceleration traces indicate that the dummy heads compressed the seat back padding to such a degree that they "bottomed out" on the steel structure underlying the padding in the seat back.
The passive occupant protection of the seating system, required by (Canadian) federal regulation since 1980 (1977 in the United States), functions as intended during frontal impacts and provides excellent protection for the occupants.
The use of lap belts in any of the 3 sizes of recent model school bus which were tested may result in more severe head and neck injuries for a belted occupant than for an unbelted on in a severe frontal collision.
The final report concluded that from these results, it must be concluded, that for frontal impacts, the restrained occupant would receive more severe head injuries than the unrestrained one. One can further conclude that injuries could very likely be life threatening.
The May 11, 1985 issue of the Insurance Institute for Highway Safety Status Report reported on seat belts in school buses and on the Canadian crash tests. The report quotes G.N. Farr, Automotive Safety Engineer with Transport Canada, and author of the School Bus Safety Study of the crash tests, as stating that "From these results it must be concluded, that for frontal impacts, the restrained occupant would receive more severe head injuries than the unrestrained one. One can further conclude that injuries could very likely be life threatening.
The Status Report article further states that "The barrier crashes of the two smaller buses showed that in all cases, the dummies secured by lap belts ,measured HIC values exceeding 1,000 - an in some cases, scores in the 2,000 plus range were calculated. All unrestrained dummies had HIC values of less than 1,000.
The test films showed that many of the belted dummies heads struck the seats in front of them so violently that the force bent the heads back on the necks al almost a 90 degree angle. This action was severe enough to be judged to cause serious injury.
In the large school buses, the HIC values for the lap belted dummies were about three times greater than for the unrestrained dummies.
It should be remembered that generally speaking, frontal collisions, particularly head on collisions between two moving vehicles, are much more severe than rear or side impact collisions.
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