Installing a cost-effective rollover protective structure (CROPS): a cost-effectiveness analysis

Cost-effective rollover protective structures (CROPS) are tractor model-specific rollover protective structures (ROPS) that are as effective as existing ROPS retrofits (passed standardized structural static testing such as SAE J2194), but less costly (less than one-half the cost of existing ROPS retrofits). This study estimated the expected effects and costs at a per-tractor level for two options: No-CROPS and Install-CROPS. Expected injuries per tractor were 0.00169 with no CROPS and 0.00016 with CROPS installed, resulting in 0.00153 injuries prevented per tractor over a 20-year period. Expected costs were $457 and $248 with and without CROPS, respectively, over the same time period, giving the cost per injury prevented as $136,601. Comprehensive sensitivity analyses indicated that the probability of an overturn is one of the most important variables. When the cost of intervention ($1,000 for purchasing, shipping, and installation of ROPS retrofit) is used in the analysis, the cost-effectiveness ratio is $497,000 per injury prevented over the 20-year period. Thus, installing CROPS instead of existing ROPS retrofits improved the cost-effectiveness ratio substantially, with a 73% reduction in the net cost per injury prevented.