[Ptero]

I disagree with you that the ICE engine has lost its usefulness. It is an incredibly sophistocated device that can achieve high relative efficiency numbers at a low production cost.

The rotary engine, like other gasoline engines, was about 15-percent thermal efficient. The Ford hydrogen fuel cell engine is around 36-percent efficient. The Hydrogen Engine Center internal combustion hydrogenengines are nearly 30-percent efficient, and some models are designed to run on ammonia, a carbonless fuel. The Aptera and Ford vehicles use electric motors.

You are never going to see a nuclear powered car, sorry. Even if you built one, we wouldn't let you drive it through our county - and we're probably not alone. There might be a scrap market for it in Afghanistan near the Pakistan border, however.