[lightsandaounds]

This phenomenon is called something like "rockets and feathers" of gas prices. I don't think anyone knows exactly why this happens, but I think it has something to do with the fact that gas stations all want to sell their gasoline at the highest price they can and rising oil prices let them raise their prices. But when oil prices fall, competitive forces act more slowly. If you run a gas station, you won't drop your price by $1 per gallon just because your costs have fallen by a $1 per gallon. You'll watch the station across the street drop his price by 5 cents, then you will drop your price by 7 cents, then he will drop his by another 5 cents and so on. The two competing stations will gradually eat away at each other's profit until the gas is back to being priced basically at cost.