Early in July, workers from the city's Department of Public Works (DPW) were completing the repaving of a stretch of road. Whinging, who had driven heavy machinery for the DPW for fifteen years, felt the brakes give away on the ten-ton roller he was driving. Whinging successfully steered the vehicle off the road into an empty field, but was crushed to death the first time the roller tumbled as it turned a half-dozen times. Whingings family sued, claiming that the roller manufacturer failed to install a roll bar "cage" around the drivers seat, and that this failure was a design defect that had resulted in Whinging's death. What theory of product liability would most likely succeed at trial? Define that theory and explain why that theory would be better than all other possible theories of liability for the manufacturing of a ten-ton roller without a "cage" around the driver's seat. Offer a prediction of the likelihood of the family's actually winning at trial using that particular theory.