• Clean and Safe Transportation



• Power to Protect: Regulatory Policy



• Consumer Protections




• Take Action!

Glossary of Rollover and Roof Crush Terms

A-Pillar – the forwardmost vertical roof support that is entirely forward of the driver’s seat and structure to hold the windshield

B-Pillar – a roof support on each side of the vehicle at the rear of the front door

CRIS – Controlled Rollover Impact System – a dynamic rollover test procedure in which the vehicle is rolled and dropped from the rear of a moving tractor-trailer.   This test is used by the automotive industry.

Dolly Rollover Test –   a dynamic rollover test procedure in which the vehicle is rolled off a moving inclined platform.   This test has been used extensively by the automotive industry.    It was presented as an optional requirement in 1971, in Federal Motor Vehicle Safety Standard 208 (Seat belts and air bags) but is not used for federal compliance measurements.

Dynamic Rollover Test – a test for rollover crashworthiness in which the tested vehicle is in a rolling motion.   A dynamic test more closely represents real-world crash conditions.

“Far” Side/ Trailing Side – It is the side of the vehicle that hits the ground second.    It is where the most crush and injury occurs.  E.g. if the driver side is the “near” side, then the passenger side is the “far” side.

FARS – Fatality Analysis Reporting System – a NHTSA database of all US fatalities in which death occurred within 30 days of the crash

FMVSS 208 – Federal Motor Vehicle Safety Standard No. 208 requiring safety belts and air bags – in a rollover context refers to the optional dolly rollover procedure

FMVSS 216 – Federal Motor Vehicle Safety Standard No. 216 – Roof Crush Resistance Standard

Inverted Drop Test – a dynamic test procedure in which the vehicle is dropped upside down on its roof from a set height; this test has been used for years by industry, but has been replaced by dolly rollover and CRIS tests.

JRS – Jordan Rollover System – a repeatable, dynamic rollover test device   created by Acen Jordan and Donald Friedman where the vehicle is rotated prior to being dropped onto a moving road surface, and is then caught before further damage can occur.

Matchboxing – when the roof moves back and forth over the occupants during a rollover crash or crash test, like a parallelogram

NASS – National Accident Sampling System – a NHTSA database of a randomly selected sample of crash investigations

“Near” Side/Leading Side – the side that hits the road first in a rollover

NHTSA - National Highway Traffic Safety Administration

NPRM – Notice of Proposed Rulemaking

Pitch Angle – the angle measured from the horizontal (longitudinal) axis of the vehicle

Repeatable – a test is repeatable if the test can be repeated many times and produces an identical or very similar result; repeatability is important for establishing whether results are the result of the test and not random error

Roll Angle – the angle measured from the horizontal (transverse) axis of the vehicle

SAFETEA-LU – Safe, Accountable, Flexible, Efficient Transportation Act: A Legacy for Users – 2005 transportation act

Static Roof Crush Test – any test for roof crush where the vehicle is not in motion and pressure is applied from above – the current FMVSS 216 test, which is the test used for determining whether a vehicle complies with federal standards, is a static roof strength test

SWR – strength-to-weight ratio; in this case, the ratio of the roof strength to the unloaded maximum curb weight of the vehicle

more resources

Because Public Citizen does not accept funds from corporations, professional associations or government agencies, we can remain independent and follow the truth wherever it may lead. But that means we depend on the generosity of concerned citizens like you for the resources to fight on behalf of the public interest. If you would like to help us in our fight, click here.