Roof Crush Test

In the test the strength of the roof is determined by pushing an angled metal plate down on one side of the roof at a slow but constant speed and measuring the force required to crush the roof.

Roof crush test. Rollover test and nass case analysis nhtsa june 1992. The number of occupant injuries is significantly higher. Although their procedure is similar to that of fmvss 216 216a the requirement to earn the highest rating is 4 0 times the vehicle s curb weight. If the vehicle being tested is a multipurpose passenger vehicle truck or bus that has a raised roof or altered roof and the initial contact point of the static loading device is on the raised roof or altered roof to the rear of the roof over the front seat area the plate is positioned so that the midpoint of the rearward edge of the lower surface of the static loading device is within 10 mm of the transverse vertical plane located at the rear of the roof over the front seat area.

Eleven midsize 4 door suv roof designs were subjected to a test similar to the one conducted by automakers to comply with federal roof strength requirements. Every year approximately 10 000 americans are killed in rollover accidents accounting for about 30 of all light vehicle occupant fatalities. The relationship between injury levels and intrusion or roof crush has. The force applied relative to the vehicle s weight is known as the strength to weight ratio.

Researchers applied force to the roofs until crush reached 10 inches measuring the peak force required for 2 inches of crush 5 inches of crush and 10 inches. Earlier in february 2009 the iihs announced a new rating system based around roof crush testing. Supplemental notice of proposed rulemaking snprm. Federal motor vehicle safety standards.

A test program like the very successful series produced by the iihs for offset frontal impacts would be more effective in the short run at least for improving roof strength. Roof crush is the failure and displacement of an automobile roof into the passenger compartment during a rollover accident. The insurance institute for highway safety has released results from its new crash test program. The recently released nhtsa study roof crush analysis using 1997 2001 nass case review which has been in the works for nearly four years reviewed nass rollover crashes in an effort to determine whether roof deformation patterns identified in an earlier agency study were still valid for current vehicle designs see upgraded rollover roof crush protection.