BP's refinery in Whiting is practically shut down for the next couple of months due to leaks/reliability issues. The fall is also maintenance season where about 10% of the capacity is coming offline for maintenance/repairs. These have huge impacts on the market when the demand is close to outstripping the supply of refined gasoline. People are buying more gasoline now that it is cheap, which is actually keeping it from being even cheaper. It's simple supply and demand.
While we have crude oil coming out of our ears, the refinery capacity has not kept up. and the crude is basically sitting in tankage/storage until it can be refined.
Here's an analogy...
We are playing a game of musical chairs when it comes to crude oil and refineries, and when the music stops, there are barrels of oil left standing without a chair (refinery). That last barrel has the price tag drop on it until it forces another barrel out of it's chair, and the process keeps repeating to the point where we are seeing oil under $40/bbl. 99% of the time it makes more sense for an oil producer to keep pumping no matter how low they drop the price, even if it is at a loss. They have bills to pay, and no way to pay them unless they keep the taps full.
When it comes to gasoline, there are chairs (customers) for every drop coming out of the refineries when the music stops - even with the refineries operating at 96% right now.
May I ask what makes you think this?
You must live in California.
Go take that up with your lawmakers who require more taxes, a different blend of gasoline, and more emission protection than the other 49 states.
This is an older map, but it will give you some insight into something that can affect gas pricing often more than taxes will:
There are more than 50 different refining companies in the US, none with more than ~10% of the market. How many choices do you have for cable? Cell phone service? etc.
You want to protect the US oil industry? Allow them to sell their product somewhere other than the United States. The export ban has created an artificially low pricing market.