Oil cost is only one factor in producing gasoline. Other activities in the refinement process probably account for the asymetric price of gasoline. That said, there are just not that many oil refiners in the USA, so some type of fiddling with refinement costs that favor the refiner is certain. Throw on top of that an oil lobby, and most of this fiddling will be deemed legal. If you want to really want to break the refiners, you have to enter that market. Considering that even at the height of the oil boom, no new refineries really opened, you can be rest assured that this price asymetry will continue.
Why Are Gas Prices Still So High? [View article]