While walking to Safeway, I passed a woman walking a dog in a wheelchair. Yes, the dog was in the wheelchair; the woman was not. This curious canine contraption consisted of a pair of wheels and an axle, on which there was a sort of blue sling to support the dog's hindquarters. There was also a metal crossbar on which the dog could prop its legs, in addition to two crossbars which seemed primarily to be there for structural stability. It was a big dog, about three feet tall at the shoulder and husky as well, so those additional crosspieces were probably necessary.
Does anyone ever do stress analyses for dog wheelchairs? What about stress tests? What factors of safety go into the design? Or are dog wheelchairs only subject to an eyeball analysis? I think there could be business opportunities for designers of high-quality pet wheelchairs -- but perhaps that's just an indication that I've never studied business.