Why have gas prices fallen so far?

This article indicates that 30% of Americans believe the drop in gas prices is at least partly due to politics.

I must say, it certainly seems likely to me. Crude oil prices are down from about $72 a barrel (at the top) to about $60 a barrel now. That's about a 17 percent drop. Meanwhile, around here, gasoline prices are down from a high slightly over $3.00 a gallon to a current price at my gas station of $2.11 a gallon. That's a drop of more than 30%.

Now, think about that for a moment. The gasoline price needs to cover a variety of costs which include a) crude oil, b) shipping to refinery, c) refining, d) shipping from refinery to gas station, and e) gasoline taxes (state and federal). All of those except the price of crude have remained the same or may even have risen. They certainly haven't fallen the way the crude price has. So, if anything, the price of gasoline should have changed by a smaller percentage than the change in the crude price. Instead, the percentage change is almost double that of the change in crude oil prices. That makes very little economic sense.

So, is it a deliberate effort by the oil giants to influence the election? I certainly can't prove it, but I do have my suspicions.