Three things here, first of all, there are a few cars in existence that do not need gas or electricity. Compressed air for example. I hear that researchers are doing anazing things using combustible materials to utilise the phase change that water undergoes. It may soon lead to a wonderous age powered by heating water until it can be used as a high pressure gas.

Objective reality does not imply consistent measurement of that reality.

Objective reality may not actually exist. Once you start throwing around relativity and quantum effects things get weird, getting them to play nicely together might be even weirder,

Several working cars do not need gas or electricity (or other source of energy).

Museum piece for example. Or super sports car that was bought as an investment and just sits in garage. Or junk car that is used as a source of spare parts. Or crash test vehicle (it is propelled with catapult). Or toy car. Or bus used for living...