An Evaluation of Production Vehicle Roof Strength

Automobile roof strength is regulated by Federal Motor Vehicle Safety Standard, FMVSS, 216, promulgated in 1971 as a temporary alternative to the dolly rollover test of FMVSS 208. The originally proposed test focused the load on the A-Pillar/Roof Rail/Header intersection and required both sides of the roof to be tested sequentially mimicking the contact sequence in a multiple rollover. The current standard is a less stringent part of the original proposal, which tests the vehicle at a shallower pitch angle with a larger platen and only stresses the first or leading side impact of the vehicle roof. A new fixture has been built that closely duplicates the originally proposed test (NHSB 1971), but with more realistic load application angles that are different on the near and far side of a vehicle during a roll. Tests performed to date illustrate the weakness of current production vehicle roofs.