Gas prices continue to slip
Average price of unleaded falls to $1.668, according to AAA survey.
NEW YORK (CNNMoney.com) -- Gasoline prices dropped for their second day in a row after four straight days of increases, according to a daily survey of gas station credit card swipes.
Regular unleaded fell 0.03 cents to a national average of $1.668 a gallon from the previous day's $1.671, according to motorist group AAA.
Prices started rising a week ago, for their first time in nearly three months, before resuming their slide. Gasoline prices have followed the price of crude oil, which has lost more than $100 a barrel since hitting a record high of $147.27 in July. Gas prices also hit a record of $4.114 a gallon in July.
In the United States, the world's largest oil consumer, drivers have cut back while supplies have risen. According to a Transportation Department report earlier this month, Americans drove 100 billion fewer miles between November 2007 and October 2008, compared with a year earlier.
Local prices: Gas is selling below $2 a gallon in every state in the Lower 48, but in Alaska, prices averaged $2.622 a gallon, and in Hawaii, they were $2.391.
Wyoming continued to post the cheapest prices, at $1.475 a gallon, according to AAA. Other states with gas below $1.50 a gallon included Utah and Missouri.
Out of major U.S. cities, Anchorage, Alaska, had the highest average gas prices, at $2.399 a gallon, according to GasBuddy.com, a service that lets motorists post local fuel prices online. Salt Lake City, Utah, had the lowest average, at $1.383.
Diesel: The price of diesel fuel, which is used in most trucks and commercial vehicles, fell by 0.09 cents from the previous day to a national average of $2.504 a gallon, according to AAA.
Diesel prices have fallen more than $2 a gallon since hitting a record high of $4.845 on July 17.
Ethanol: The price of E85, an 85% ethanol blend made primarily from corn, rose by 0.01 cents to an average of $1.499 a gallon in Saturday's survey, according to AAA.
E85 can be used in place of regular gas in specially configured "flex-fuel" vehicles, but it is not readily available in some states.
The AAA figures are statewide averages based on credit card swipes at up to 100,000 service stations across the nation. GasBuddy prices are averages of local regular unleaded gasoline prices that about 700,000 volunteer gas prices spotters have posted online. Individual drivers may see lower fuel prices in different areas of each state 
