Gas prices have advanced sharply in recent days partly because refiners have been switching over from selling winter grade gasoline to the more expensive but less polluting form of the fuel the government requires them to sell in the summer. That process, which made winter grade fuel more scarce, is nearly complete now, suggesting that price increases could slow.
"That was probably why ... you saw (prices) accelerate so quickly," said Tom Kloza, publisher and chief oil analyst at the Oil Price Information Service in Wall, N.J. "No, don't get used to these crazy increases." - Associated Press
This is just an environmentalist ploy. The tree huggers are working directly with the oil conglomerates and their goal is to keep increasing the prices so that people will be forced to walk instead of "destroying the planet"