Gas prices continue retreat

The average price of gas has dropped below $3.90 a gallon, but there are still many states where it tops $4.

NEW YORK (CNNMoney) -- The price of an average gallon of regular gasoline declined for the third straight day Thursday, putting a crimp -- at least temporarily -- in one of the fastest and steepest runups in recent memory.

The average price fell 0.8 cent a gallon to $3.891 in the latest daily survey conducted for the motorist group AAA, after dipping to $3.899 on Wednesday. The price has fallen about 2 cents in the past week.

Despite the retreat, gasoline still averages more than $4 a gallon in 8 states and the District of Columbia. At nearly $4.61 a gallon, Hawaii has the nation's highest pump price.

Wyoming has the nation's lowest gas prices, averaging just above $3.64 a gallon.

The decline mirrors a moderate drop in crude oil prices, which account for roughly 70% of the cost of gas. The latest Lundberg Survey found that gas may be at its peak if the price of crude holds steady.

Crude prices have fallen for a few reasons, but the biggest is Iran's decision to negotiate over its nuclear program. Other factors include assurances from Saudi Arabia that it can cover any loss of oil from Iran; easing demand in the U.S. due to the economy; and a pipeline reversal that will add more oil to global markets.

However, all analysts warn that the situation can turn quickly, and some remain skeptical that Iran will stay out of the headlines throughout the summer. Gasoline prices could also rise as the industry switches over from winter gas to cleaner summer blends.