When car makers came up with new concepts in the 1950s, they really pushed the boundaries. Nothing was out of reach, which is why the Ford Nucleon wasn't intended to be powered by an internal combustion engine. Instead, in the back, looking much like a spare wheel there was a steam engine powered by uranium fission, along the lines of those found in nuclear-powered submarines of the time.
Unveiled in 1958, the Nucleon never got beyond the 3/8th-scale model stage. Ford's thinking was that with nuclear power becoming increasingly popular, it would be only a matter of time before the technology had been miniaturised enough to be a viable means of propulsion for personal road transport.
The idea was that the Nucleon wouldn't need to be refuelled until anywhere between 5000 and 10,000 miles. At this point the reactor would be topped up with uranium pellets which would be converted to steam, and the Nucleon was then good for another 5000-10,000 miles. So a driver could set off on their 5000-mile journey and they could undertake the entire trip with no need to stop. Apart from maybe a comfort break at the mid-way point.
When the Nucleon was being designed, the US was stockpiling huge amounts of uranium and plutonium for use in weapons. The thinking was that there would be plenty to go round if it was needed for powering anything from domestic appliances to cars and other modes of transport. What hadn't been considered was how to dispose of this spent uranium and plutonium. Bearing in mind just what a headache this has become for the nuclear power ndustry, perhaps it's just as well that we don't now have hundreds of millions of cars around the world, all powered by nuclear fuels.