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On the Stability of the EPA MPG Adjustment Factors
ISSN: 0148-7191, e-ISSN: 2688-3627
Published June 01, 1985 by SAE International in United States
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The offset (sometimes called “shortfall”) between EPA MPG and actual in-use MPG has been shown to be dependent upon vehicle technology and EPA MPG level. If these variables change significantly, there is the potential for the constant EPA MPG adjustment factors (0.90 city, 0.78 highway) to become obsolete.
Trends in passenger car MPG have been used to formulate a model of vehicle technology mixes and MPG levels over the next 15 years, to investigate the degree to which MPG adjustments derived from such a scenario might differ from the promulgated constant adjustment factors.
As a check on the reasonableness of the future technology scenario, a simple econometric model was constructed independently which relates car class market fractions and MPG levels to gasoline price, and to regulatory requirements: MPG Standards and the Gas Guzzler tax. It is shown that the technology scenario’s fleet MPG is consistent with that of the econometric model, when the latter uses a trend leading to a fuel price of about $2.25/gallon in the year 2000.
It is shown that, at fleet level, the technology scenario for technology and MPG changes does not obsolete the current MPG adjustment factors.
CitationHellman, K. and Murrell, J., "On the Stability of the EPA MPG Adjustment Factors," SAE Technical Paper 851216, 1985, https://doi.org/10.4271/851216.
- Heavenrich Murrell Cheng, Loos, “Light-Duty Automotive Fuel Economy … Trends through 1985” SAE Paper 850550 1985
- Hellman Murrell, “Why Vehicles Don’t Achieve EPA MPG On the Road and How That Short-fall Can Be Accounted For” SAE Paper 820791 1982
- Murrell Hellman, “Development of Adjustment Factors for the EPA City and Highway MPG Values” SAE Paper 840496 1984
- Comments of the Department of Energy on EPA Rulemaking to Adjust the EPA Label MPG Values 1983
- “Energy Projections to the Year 2010” U.S. Department of Energy, Office of Policy, Planning and Analysis 1983
- Personal Communication Atlantic Richfield Company, Corporate Planning 1984