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Auto Club Study Shows Alternate Test More Accurately Measures Motorists' "Real World" Miles Per Gallon


Study Confirms EPA Heading in Right Direction in
Revising Process for New Car Fuel Economy Labeling

(LOS ANGELES, JAN. 10, 2006) — AAA today released a new report conducted by the Automobile Club of Southern California's Automotive Research Center (ARC) that confirms the need to revise testing procedures for fuel economy labeling so that consumers can make informed decisions when they purchase new vehicles. The study also demonstrates that at least one existing Environmental Protection Agency test — known as the USO6 emissions certification test — comes closer to reflecting real world driving conditions and more accurately estimates fuel economy.

The release of the report coincides with the EPA's announcement of proposed new fuel economy labeling procedures and confirms that the agency is taking an important step in committing to change the way it calculates fuel economy. The existing testing procedures for fuel economy labeling are 30 years old.

"Car buyers need more accurate fuel economy information, and our study shows that the EPA can provide it with existing testing procedures," said Steven Mazor, Manager of the Automotive Research Center of the Auto Club. "Our research confirms the current testing system EPA uses to determine miles-per-gallon ratings in many instances significantly over estimates real world mpg ratings because it does not account for the way we drive today. The USO6 test does a better job of estimating mpg and it can be done without requiring manufacturers to create a new and costly testing system."

Using their state-of-the-art emissions and vehicle test laboratory, the Auto Club's ARC technicians gathered owner mpg data from 41 vehicles, representing 18 models that include the most popular vehicles on the road today. These data were collected through a series of rigorous scientific tests that included: gathering motorists' actual mileage over at least a one-month period, testing at least one of each model in the laboratory, and measuring fuel economy by driving the cars tested in the lab over a 100-mile standardized loop.

The results show that 90 percent (36 out of 41) of the vehicles experienced mileage worse than the current EPA estimate — by an average of four mpg and an average deviation of 15.7 percent. ARC researchers then conducted a series of tests using an existing EPA test typically used for monitoring emissions called the "USO6" test. This test simulates aggressive driving, congestion and high speeds. The results show that the USO6 test resulted in only a one mpg, or a 4.4 percent deviation, from the "real world" test.

Starting last year, the Auto Club and AAA joined leaders in Congress to call on the EPA to address the disparity between the EPA sticker rating and the mileage motorists were actually getting on the road. The proposal announced by the EPA Administrator today demonstrates a willingness on the part of the agency to try a new approach that will lead to more accurate information for consumers, according to AAA. Mazor added that this research also illustrates that the way a person drives directly impacts the mileage they are likely to see, and drivers can play a crucial role in achieving the best mileage possible from their vehicles. MPG varied significantly with the same models when vehicles were driven differently, according to the Auto Club's ARC test.

"Motorists should know that there will never be a perfect test for determining their mileage," said Mazor. "However, if we want to maximize our mileage and be sensitive to our environment, we must remember that how we maintain our vehicle and how we choose to drive significantly contributes to saving money at the gas pump and conserving fuel."

Vehicle tests were performed at the Automotive Research Center of the Automobile Club of Southern California located in Diamond Bar, Calif. The Auto Club is the Southern California AAA affiliate and has been performing emissions testing since the early 1970s.

The Automobile Club of Southern California, the largest affiliate of the AAA, has been serving members since 1900. Today, the Auto Club's members benefit by roadside assistance, insurance products and services, travel agency, financial products, automotive pricing, buying and financing programs, automotive testing and analysis, trip planning services and highway and transportation safety programs. Information about these products and services is available on the Auto Club's Web site at


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The Automobile Club of Southern California is a member club affiliated with the American Automobile Association (AAA) national federation and serves members in the following California counties: Inyo, Imperial, Kern, Los Angeles, Mono, Orange, Riverside, San Bernardino, San Diego, San Luis Obispo, Santa Barbara, Tulare, and Ventura.