Click on “Download PDF” for the PDF version or on the title for the HTML version.

If you are not an ASABE member or if your employer has not arranged for access to the full-text, Click here for options.

The great increase in maximum laden mass and recent fatal accidents involving tractors having ROPS tested in accordance with a specific standard have led to the need to evaluate the validity of the current standards for testing ROPS. A ROPS able to meet the requirements of the current tests, but without a rollover safety margin, has been designed. This means that it is possible to manufacture ROPS without sufficient safety but that could still be successfully tested in accordance with the current standards. A proposal has been developed to improve the standards by using the maximum laden mass as the reference mass as well as modifying the coefficients in their formulae. The proposed methodology recognizes the validity of the current Code 4 and SAE J2194 formulae for tractors with additional ballast mass that is less than 35% of their unladen mass. The proposed methodology would provide adequate and homogeneous safety for all tractors, equivalent to the safety provided by the current Code 4 standard for tractors whose maximum laden is 135% of their unladen mass. If the current formulae are not modified, then their validity should be limited to a safety margin of maximum laden mass equivalent to 135% of the reference mass.