World fought over oil but cars ran using nuclear power. Shouldn't they fight over maybe plutonium or uranium? This is very odd and I am not sure if anyone explained this. In Fallout 3, New Vegas as well as Fallout 2 the cars run of Microfusion Cells wich is nuclear. What did they need oil for? Petroleum plastics, fertilizer but the most common use is fuel. Since cars in Fallout world ran via nuclear power, petroleum would be useless. In a sense in Fallout timeline all energy was switched from petroleum to nuclear power.