Because of house and work I’ve missed much of the gas price hoopla over the past month. Others have been paying attention, though, and I recommend this post from Steve Verdon for its wealth of quantitative analysis and information.
Retail gasoline prices react to crude oil prices in a “rocket and feathers” pattern: when crude rises, retail prices shoot up, and then float back down. Most empirical studies of this phenomenon find that all of the crude price decrease is typically reflected in the retail price decrease within two weeks.