Re: Rocket powered
I like your thinking, a steam powered car would be a more sensible option for transport after 2040. True Stephenson's original was a bit slow, but this bad boy, "The fastest kettle in the world", can do over 140 mph*.
(*Needs a bit of a run up to get to that speed, preferably a nice flat 2 mile runway. Also emits copious qualities of DHMO)