The AAA Fuel Gauge Web Site is derived from credit card transactions at more than 85,000 stations around the country. Prices shown are combined averages of the last card swipe of the previous day. The following schedule is used for price updates:

• Prices shown on Wednesday are based on the last credit card swipe at each station on Tuesday.
  
• Prices shown on Thursday are based on the last credit card swipe at each station on Wednesday.
  
• Prices shown on Friday are based on the last credit card swipe at each station on Thursday.
  
• Prices shown on Saturday are based on the last credit card swipe at each station on Friday
  
• Prices shown on Sunday are based on the last credit card swipe at each station on Saturday
  
• Prices shown on Monday are based on the last credit card swipe at each station on Sunday.
  
• Prices shown on Tuesdays are based on the last credit card swipe at each station on Monday.
  
• Crude oil price is based on the West Texas Intermediate closing prices on the New York Mercantile Exchange and converted from price per barrel to a per gallon price. There are 42 gallons in each barrel. The wholesale price is based on the combined average of all the terminals in the United States tracked by OPIS.
  
• The “E85 MPG/BTU adjusted price” represents the adjusted E85 cost to regular unleaded gasoline. According to the Energy Information Agency, the average E85 is 94,190 BTU assuming a year-round ethanol content of 74% and regular gasoline averages 124,000 BTU. The adjusted E85 MPG/BTU price reflects how much a consumer would have to pay for E85 gas to receive the same fuel efficiency as regular unleaded gas

AAA's Daily Fuel Gauge Report is the most comprehensive retail gasoline survey available.  Everyday up to 85,000 self-serve stations are surveyed.

Data provided by Oil Price Information Service