If you are running low on fuel in a gasoline powered car I guess driving at a constant speed is best and turning off stuff like the AC would be wise .
I suppose keeping the car in a reasonably high gear would be good too?
The question is what is the best speed?
If too fast air drag will suck the gas but if too slow the poor part load efficiency of the Internal combustion engine would burn the fuel anyway.
Is this speed higher for larger cars?
Is this speed quite broad ?
Is it different for a diesel ?
What would be the story for an electric car ?
would the optimum speed be real slow ?