On April 30, 2009, NHTSA released a final rule that upgrades the agency’s roof crush standard as follows:
For the vehicles currently subject to the standard (i.e., passenger cars and multipurpose passenger vehicles, trucks and buses with a GVWR of 2,722 kilograms (6,000 pounds) or less, the rule doubles the amount of force the vehicle’s roof structure must withstand in the specified test, from 1.5 times the vehicle’s unloaded weight to 3.0 times the vehicle’s unloaded weight.
The rule extends the applicability of the standard so that it will also apply to vehicles with a GVWR greater than 2,722 kilograms (6,000 pounds), but not greater than 4,536 kilograms (10,000 pounds). The rule establishes a force requirement of 1.5 times the vehicle’s unloaded weight for these newly included vehicles.
The rule requires all of the above vehicles to meet the specified force requirements in a two-sided test, instead of a single-sided test (i.e., the same vehicle must meet the force requirements when tested first on one side and then on the other side of the vehicle).
The rule establishes a new requirement for maintenance of headroom (i.e., survival space, during testing in addition to the existing limit on the amount of roof crush).
The rule also includes a number of special provisions, including ones related to leadtime, to address the needs of multi-stage manufacturers, alterers, and small volume manufacturers.
For passenger cars and MPVs, trucks and buses with a GVWR of 2,722 kilograms (6,000 pounds) or less, the phase-in begins on September 1, 2012. By September 1, 2015, all of these vehicles must meet the upgraded requirements, with certain exceptions. Vehicles produced in more than one stage and altered vehicles need not meet the upgraded requirements until September 1, 2016.
MPVs, trucks and buses with a GVWR greater than 2,722 kilograms (6,000 pounds) and less than or equal to 4,536 kilograms (10,000 pounds) must comply with applicable requirements beginning September 1, 2016, with certain exceptions. Vehicles produced in more than one stage and altered vehicles need not meet the requirements until September 1, 2017.
