Federal Motor Vehicle Safety Standards; Roof Crush Resistance

Zusammenfassung

This document proposes to revise the test procedures in Standard No. 216, Roof Crush Resistance, to make them more suitable to testing vehicles with highly sloped roofs or raised roofs. The current test procedure is intended to test the strength of the roof over the driver. It involves lowering a large test plate, inclined forward at a five degree angle, to an initial contact point near the leading edge of the roof. However, when the procedure is performed on certain rounded, aerodynamically-shaped roofs that may themselves slope at more than five degrees, small differences in test plate angle result in considerable variability in the location of the initial contact point, thus reducing the repeatability of the test results. Similarly, for vehicles with raised, irregularly shaped roofs (such as some converted vans), the initial contact point may not be above the driver, but on the raised rear portion of the roof, behind the driver. This proposal addresses these problems by specifying the use of a smaller test plate for use on vehicles on which the use of the current larger test plate would result in an initial contact point behind the driver. The rearward edge of the smaller test p