I came across an interesting video by Bob Lazar on YouTube . Bob Lazar explains how he runs his car off water / hydrogen
Two problems with that, did not see a link, first is the energy needed to break the water down into Hydrogen and Oxygen, where does that come from? And second storing and transporting the hydrogen safely and in large enough quantities to be practical. Solve those two "minor" problems and you will be a rich man!
https://youtu.be/fD0rrq7BKX8
"Fetch me a bucket of Hydrogen fuel please".... Second problem, you burn 2 parts H for every part O, gasoline IIRC is 1800 O to fuel. So your gonna be carrying a whole bunch of it.
Might want to put out that ciggy before filling the bucket!