Any motorized vehicle used to transport people and cargo by road or rail depends on electric power for either direct propulsion  with electric motors or the refining of crude oil into gasoline or diesel fuel.

Oil refineries are Hugh consumers of electric power, millions of megawatts. They need a constant supply of power to operate hundreds of electric motors the operate pumps and valves. Without the electricity they  shut down immediately. Much of the hot liquid distillate trapped in the thousands of feet of pipes and pumping equipment solidifies.

If the refineries loose power for even a few days the supply system will be seriously disrupted causing fuel shortages and very high prices even far away from the target cities.