Gasoline and Diesel Fuel Update

Previous Diesel Fuel Price Data Collection Procedures

Every Monday, retail on-highway diesel prices are collected by telephone and fax from a sample of approximately 350 retail diesel outlets, including truck stops and service stations. The data represent the price of ultra low sulfur diesel (ULSD) which contains less than 15 parts-per-million sulfur. The Environmental Protection Agency (EPA) requires that all on-highway diesel sold be ULSD by December 1, 2010 (September 1, 2006 in California). In January 2007, the weekly on-highway diesel price survey began collecting diesel prices for low sulfur diesel (LSD) which contains between 15 and 500 parts-per-million sulfur and ULSD separately. Prior to January 2007, EIA collected the price of on-highway fuel without distinguishing the sulfur level. On February 19, 2007 EIA began releasing the detailed sulfur price information that was determined to be accurate. The publication of Low Sulfur On-Highway Diesel Prices at the U.S. level was discontinued December 8, 2008. At that time, the LSD price estimates at the U.S. level no longer met accuracy requirements due to a diminishing number of stations selling LSD as a result of the EPA's regulations on on-highway diesel fuel. EIA continued to collect LSD prices from the retail outlets in the survey sample and included them in the average prices of all types of diesel. By July 26, 2010, the two price series converged since there were no outlets reporting Low Sulfur On-Highway Diesel (LSD) fuel prices on EIA's price survey. As of December 1, 2010, any on-highway diesel fuel sold is ULSD.

The prices reported in this survey are subjected to automated edit checks during data collection and data processing. Data flagged by the edits are verified with the respondent. Imputation is used for companies that can not be contacted. The average survey response rate for 2009 was 99.7%.

The price estimates each week are obtained using simple averages at the sampling cell level. For publication regions that constitute a combination of sampling cells, the volume of on-highway diesel sold in that region as reported in the EIA-782 monthly survey is used to weight the sampling cells and obtain publication level prices for on-highway diesel.

The average prices are released by 5:00 P.M. Monday, except on government holidays, in which case the data are released on Tuesday (but still represent Monday's price). These data are made available through EIA's hotline (202-586-6966), EIA's web page, and through EIA's E-mail notification, regular and wireless.