In Australia, all new earth moving vehicles used in mining and quarry sites are required by law to be fitted with an approved Roll-Over Protection System (ROPS), as detailed in the standard AS 1224-1994.However, there are many old vehicles without ROPS, used by small scale owners. The owners are now required to retrofit their vehicles with ROPS and to prove that they comply with the requirements of the standard. However, physical tests are necessarily destructive, causing unavoidable damage not only to ROPS, but in some cases even to the expensive vehicle.To boost workplace safety on mining and quarry sites in Victoria, the State Government has announced a new initiative, accompanied by financial support, to help operators to fit roll bars and seat-belts to their vehicles, and to assess them by computer simulation of the prescribed physical tests.The procedure for the compliance by computer simulation is demonstrated on one real case, involving a “one off”, self-made ROPS. Static tests are simulated first, followed by the simulation of dynamic roll-over in order to evaluate a recent criticism on the adequacy of the AS 124-1994 for the protection of drivers in real roll over accidents. Finally, the self-made ROPS design of the discussed case is evaluated and modified to demonstrate that not only a substantial weight reduction is possible, but also that a lighter ROPS may improve passive safety of operators.