Performance standards for roll-over protective structures (ROPS) have been developed for four classes of equipment-TTT, loaders, motor graders, and wheel scraper prime movers. The criteria were developed by studying the behavior of roll-proven structures in a laboratory and converting these observations into numerical relationships.The criteria establish five major requirements: 1. Resist horizontal force-related to machine weight. 2. Absorb energy-must deflect without catastrophic failure. 3. Withstand vertical load after deflection equal to machine weight. 4. Meet above requirements without entering critical zone. 5. Must perform at 0 F or material must exhibit Charpy “V” notch impact strength of 8 ft-lb at -20 F.