Testing methods and SAE Recommended Practices were developed for evaluating both the ability of a truck cab to resist roof loading in a rollover environment and the occupant kinematics and injury potential for occupants in a 90-degree heavy truck rollover. In evaluating a heavy truck roof for its ability to resist rollover loads, real-world accident data was analyzed and full-scale tests were performed to define the rollover environment. It was found that testing methods currently in place for passenger cars were not sufficient to represent the loading mechanisms that typically occur in a heavy truck rollover. An SAE Recommended Practice (RP) for both dynamic and quasi-static roof load testing was developed, and tests were conducted to evaluate their use. To evaluate heavy truck occupant safety in a 90-degree rollover, independent of roof intrusion, a rollover simulator was developed. The simulator allows occupant restraints, seats, and interiors to be evaluated for injury mechanisms. An RP for the full cab rollover simulator was written and evaluated with a series of tests.