Oil and gas: supply and demand.
Without taking a specific areas' taxes into account, it is all really just supply and demand; both on the crude oil prices and the cost we see at the pump.
Don't forget that oil is bought and sold on a world commodities price basis. The big oil companies make their money by selling oil in barrels not gasoline in gallons.
Many oil companies would prefer not to sell gasoline at retail locations. In fact, most retail stations now make more profit in the convenience store side of the retail outlet.
I have stated this before but once again; a huge part of the issue is the lack of excess supply. Many refineries are land locked and unable to expand to dramatically increase throughput and no one wants to allow new refineries to be built in their back yards.
As a result, unless we conserve and reduce the amount of gasoline we use, the price will not come down.
All of that being said; OPEC does a great job of controlling the flow of crude to maintain an certain amount on the world market. This causes prices to fluctuate within a fairly narrow range that they feel will cause the demand to stay stable. They won't allow prices to get so high that governements get upset or consumers find permanent ways to stop using oil base products.
There is a certain number of people that feel that Iran ( and other countries) often causes turmoil in the world in an attempt to cause fear in the oil markets and therefore increasing the short term price per barrel costs of oil. This results in dramatically higher revenues for the Iranian government in the time period of a given incident. Look at the recent issue with the British sailors for example.
An interesting theory to say the least.
Just my 2 cents which is probably only worth a penny,
Greg Ladd