Successful development of a product requires the consideration and balancing of many design parameters. Proposals to modify designs that have been fully implemented and put into production are often made by people who were not involved in the original design process. Such proposals, commonly focusing on a specific aspect of the product, must be evaluated in the context of the overall product and its intended use by consumers; a design change may improve performance in one area but compromise performance in another, or even introduce new problem areas.As a case in point, several proposals have been made for operator protection systems with the claim that they would reduce the frequency and severity of injuries associated with All Terrain Vehicle (ATV) operation. For example, Johnson, Carpenter, Wright & Nelson (1991) considered selected accident modes and proposed a set of design changes involving a rollover protection system (ROPS) and significant vehicle modifications. In this paper, the design concept is evaluated in more detail.A full-scale operating model of the proposed four-wheel vehicle prototype was built; systematic comparisons to ATVs were made considering mobility, utility, performance, and occupant protection. It was found that the proposed vehicle modifications in fact produce a new vehicle type with significantly reduced utility and performance compared to ATVs, without the likelihood of reducing the accident and injury risk associated with the use of the vehicle. Unlike existing ATVs, the Johnson et al. design does not appear to be a viable approach to balancing utility and safety. This outcome is consistent with other analyses and with the general conclusions reached by the Consumer Product Safety Commission (CPSC).