Many rollover accidents involve loading to the roof structure with forces that include vertical, lateral and longitudinal components. Many traditional test methods focus on the lateral and vertical components without a dynamic longitudinal component. SAFE Laboratories has now developed a test method that allows for a roof to be loaded in all three directions at once. One recent study involved a rollover onto a guardrail with a combination of translational and vertical motion.  The impact caused damage to the roof structure compromising the occupant survival space. 

Suspended from a carriage and sliding along a cantilevered beam, the test vehicles were set to a precise orientation.  A system of falling weights and cable was used to accelerate the carriage in order to impart the required translational energy and velocity to the test vehicles.  The test vehicles were released into freefall when the carriage rolled off the end of the beam.  A production vehicle and a vehicle modified with an alternative roof design were dropped onto the guardrail under identical conditions allowing evaluation of the effect of structure changes on the occupant’s survival space.