Definitions, Sources and Explanatory Notes

 Category:   Petroleum Prices
 Topic:   Weekly Retail Gasoline and Diesel Surveys

  Definitions

Key Terms Definition
Conventional Area Any area that does not require the sale of reformulated gasoline. All types of finished motor gasoline may be sold in this area.
Conventional Gasoline Finished motor gasoline not included in the reformulated gasoline category. Excludes reformulated gasoline blendstock for oxygenate blending (RBOB) as well as other blendstock. Note: this survey designates all motor gasoline collected within a conventional area as conventional gasoline (see conventional area).
Gasoline Grades The classification of gasoline by octane ratings. Each type of gasoline (conventional and reformulated) is classified by three grades - regular, midgrade, and premium. Note: gasoline sales are reported by grade in accordance with their classification at the time of sale. In general, automotive octane requirements are lower at high altitudes. Therefore, in some areas of the United States, such as the Rocky Mountain States, the octane ratings for the gasoline grades may be 2 or more octane points lower.
Low Sulfur Diesel Fuel Diesel fuel containing more than 15 but less than 500 parts per million (ppm) sulfur.
Midgrade Gasoline Gasoline having an antiknock index, i.e., octane rating, greater than or equal to 88 and less than or equal to 90. Note: Octane requirements may vary by altitude.
Nonattainment Area Any area that does not meet the national primary or secondary ambient air quality standard established by the Environmental Protection Agency for designated pollutants, such as carbon monoxide and ozone.
On-Highway Diesel Includes sales for use in motor vehicles. For purposes of this survey, it is designed to estimate the retail cash price of self-serve, motor vehicle diesel fuel.
OPRG "Oxygenated Fuels Program Reformulated Gasoline" is reformulated gasoline which is intended for use in an oxygenated fuels program control area during an oxygenated fuels program control period.
Petroleum Administration for Defense District (PADD): PADD 1 (East Coast):
   PADD 1A (New England): Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, Vermont.
   PADD 1B (Central Atlantic): Delaware, District of Columbia, Maryland, New Jersey, New York, Pennsylvania.
   PADD 1C (Lower Atlantic): Florida, Georgia, North Carolina, South Carolina, Virginia, West Virginia.
PADD 2 (Midwest): Illinois, Indiana, Iowa, Kansas, Kentucky, Michigan, Minnesota, Missouri, Nebraska, North Dakota, Ohio, Oklahoma, South Dakota, Tennessee, Wisconsin.
PADD 3 (Gulf Coast): Alabama, Arkansas, Louisiana, Mississippi, New Mexico, Texas.
PADD 4 (Rocky Mountain): Colorado, Idaho, Montana, Utah, Wyoming.
PADD 5 (West Coast): Alaska (North Slope and Other Mainland), Arizona, California, Hawaii, Nevada, Oregon, Washington.
Premium Gasoline Gasoline having an antiknock index, i.e., octane rating, greater than 90. Note: Octane requirements may vary by altitude.
Reformulated Area An ozone nonattainment area designated by the Environmental Protection Agency which requires the use of reformulated gasoline. Includes oxygenated fuels program reformulated gasoline (OPRG).
Reformulated Gasoline Finished motor gasoline formulated for use in motor vehicles, the composition and properties of which meet the requirements of the reformulated gasoline regulations promulgated by the U.S. Environmental Protection Agency under Section 211(k) of the Clean Air Act. (Details on this clean fuel program). This category includes oxygenated fuels program reformulated gasoline (OPRG) but excludes reformulated gasoline blendstock for oxygenate blending (RBOB). Note: this survey designates all motor gasoline collected within a reformulated area as reformulated gasoline (see reformulated area).
Regular Gasoline Gasoline having an antiknock index (average of the research octane rating and the motor octane number) greater than or equal to 85 and less than 88. Note: Octane requirements may vary by altitude.
Total Gasoline Includes all finished motor gasoline grades (regular, midgrade, premium) and formulations (conventional, reformulated).
Ultra Low Sulfur Diesel Fuel Diesel fuel containing a maximum 15 parts per million (ppm) sulfur.

For definitions of related energy terms, refer to the EIA Energy Glossary.

  Sources

Form EIA-878, "Motor Gasoline Price Survey" ( Form, Instructions, Sample Methodology )
Form EIA-888, "On-Highway Diesel Fuel Price Survey" ( Form, Instructions, Sample Methodology )

  Explanatory Notes

  		• Every Monday, retail prices for all three grades of gasoline are collected by telephone from a sample of approximately 800 retail gasoline outlets. The prices are published around 5:00 p.m. ET Monday, except on government holidays, when the data are released on Tuesday (but still represent Monday's price). The reported price includes all taxes and is the pump price paid by a consumer as of 8:00 A.M. Monday. This price represents the self-serve price except in areas having only full-serve. The price data are used to calculate weighted average price estimates at the city, state, regional and national levels using sales and delivery volume data from other EIA surveys and population estimates from the Bureau of Census.
  		• Every Monday, cash self-serve on-highway diesel prices (including taxes) are collected from a sample of approximately 400 retail diesel outlets in the continental U.S. The sample includes a combination of truck stops and service stations that sell on-highway diesel fuel. The data represent the price of ultra low sulfur diesel (ULSD) which contains less than 15 parts-per-million sulfur. All collected prices are subjected to automated edit checks during data collection and data processing. Data flagged by the edits are verified with the respondents. Imputation is used for companies that cannot be contacted and for reported prices that are extreme outliers. The average survey response rate for 2012 was 99%. Average national and regional prices are released around 5:00 p.m. ET on Mondays, except on government holidays, in which case the data are released on Tuesday (but still represent Monday's price).
  		• Publication of Low Sulfur On-Highway Diesel (LSD) prices at the U.S. level was discontinued on December 8, 2008 due to a diminishing number of stations selling LSD as a result of EPA Diesel Fuel Regulations. EIA continued to collect LSD prices from retail outlets and included them in the Diesel Average All Types price until July 26, 2010, when no more outlets reported LSD sales. Beginning July 26, 2010 publication of Ultra Low Sulfur Diesel (ULSD) price became fully represented by the Diesel Average All Types price. As of December 1, 2010 (September 1, 2006 in California), any on-highway diesel fuel sold is ULSD as mandated by EPA on-highway diesel fuel regulations.
  		• EIA did not collect weekly retail motor gasoline data between December 10, 1990 and January 14, 1991.
  		• Monthly and annual averages are simple averages of the weekly data contained therein. For months and years with incomplete weekly data series, the monthly and/or annual averages are not available.
  		• Map of reformulated gasoline areas.
  		• Map of PAD Districts and Federal/State motor fuel tax table