Why when oil goes up a dollars a barrel, prices soar. But when it drops $15 a barrel gas only drops a penny?

It is known as the law of supply, and stealing.Why when oil goes up a dollars a barrel, prices soar. But when it drops $15 a barrel gas only drops a penny?
gasoline is about 5% the cost of a barrel of oil and the price of a barrel is for delivery in a month or two. Also the fact that the oil companies will only charge what the consumer can tollerate. So $140 oil should be $7.50 a gallon gas, but that would put the US economy in crisis, the oil companies know that. They charge what we can pay. Check out the cost of gas in other contries.Why when oil goes up a dollars a barrel, prices soar. But when it drops $15 a barrel gas only drops a penny?
trickle down economics.
True, BUT what can we do ???