We would fugure out something. At least I would. Theres ethanol. If we had no oil we would just convert to electric/ethanol combination engines, they have less power but they still work. Hydroelectric Damns can produce powEr, coal, coal liquification, solar power, shale oil, EVEN HYDROGEN/OXYGEN which releases more energy that gasoline fraction pertol distillate. Shit I would just start distilling and producing myself on small personal scale with my good old copper moonshine still.

http://www.coppermoonshinestills.com/