The price of gasoline is directly connected to the price of crude oil. In theory, oil prices fluctuate based on supply and demand. However, oil prices are in fact controlled by oil futures contracts traded on futures exchanges. The price of these crude oil futures is the direct result of what investors *think* the price of oil will be in the future. If investors think oil is going to be more expensive (e.g. due to an improving economy or a potential conflict in an oil-producing region), they bid these prices up. This self fulfilling prophecy creates an artificial asset bubble and anyone who drives a car ends up paying for it.
Remove the financial incentive of trading crude oil futures by establishing a special tax on oil future profits