Why U.S. Gas Prices Haven't Fallen More
No, the reason for this is that the official quoted price is for West Texas Intermediate crude (WTI), a high quality sort drilled exactly where the name suggests it is drilled. But most gasoline is made of imported lower quality varieties. And because demand has fallen more in America than elsewhere, the WTI has fallen a lot more than other oil. Usually, the imported stuff has been cheaper which is why refineries have focused on them, but now unusually enough, the WTI is actually cheaper.
Refineries could of course invest so that they will be able to use WTI, but that will take years, and given how volatile oil prices have been, they can't be sure that WTI will really stay cheaper. And indeed, if these investments were made, that in itself would push up the price of WTI relative to other oil. So for now, gasoline in America won't be as cheap as you would expect from the price of oil usually quoted in the financial media.