The title question, “Why are gasoline prices so high?”, or some variant has been the primary driver of new viewers from search engines to Knowledge Problem over the past three or four weeks.
Crude oil prices are higher than last Spring, but no recent hurricane damage to oil production areas, unlike Fall of 2005. Otherwise those posts cover the basic points.
One thing that is not driving up the price of gasoline, except maybe by a fraction of a hairsbreadth, is the purchase of crude oil for injection into the Strategic Petroleum Reserve, as John Whitehead demonstrates at Environmental Economics. Read Evan Herrnstadt at Common Tragedies for links to more.