01020434

Component

https://doi.org/10.3141/1983-14

http://scholar.google.com...orek&publication_year=2006

The usefulness of the U.S. Environmental Protection Agency’s (EPA) passenger car and light truck fuel economy estimates has been the subject of debate for the past three decades. For the labels on new vehicles and the fuel economy information given to the public, the EPA adjusts dynamometer test results downward by 10% for the city cycle and 22% for the highway cycle to better reflect real world driving conditions. These adjustment factors were developed in 1984 and their continued validity has repeatedly been questioned. In March 2005, the U.S. Department of Energy and EPA’s fuel economy information website, www.fueleconomy.gov, began allowing users to voluntarily share fuel economy estimates. This paper presents an initial statistical analysis of more than 3,000 estimates submitted by website users. The analysis suggests two potentially important results: (a) adjusted, combined EPA fuel economy estimates appear to be approximately unbiased estimators of the average fuel economy consumers will experience in actual driving, and (b) the EPA estimates are highly imprecise predictors of any given individual’s in-use fuel economy, an approximate 95% confidence interval being ±7 mpg. These results imply that what is needed is not less biased adjustment factors for the EPA estimates but rather more precise methods of predicting the fuel economy individual consumers will achieve in their own driving.

01041874

English

pp 99-105

2006

Transportation Research Record: Journal of the Transportation Research Board

0309099935

Print

Figures (3) ; References (14) ; Tables (4)

Adjustment factors; Automobiles; Consumers; Estimates; Fuel consumption; Light trucks; Statistical analysis; Websites (Information retrieval)

U.S. Environmental Protection Agency

Reporting

Data and Information Technology; Energy; Environment; Highways; Vehicles and Equipment; I15: Environment; I96: Vehicle Operating Costs

TRIS, TRB, ATRI

Mar 3 2006 10:58AM

• Comparison of Buyers of Hybrid and Conventional Internal Combustion Engine Automobiles: Characteristics, Preferences, and Previously Owned Vehicles
• Detailed Analysis of Urban Station Siting for California Hydrogen Highway Network
• Environmental Justice Assessment in Racially Diverse Areas
• Environmental Justice Concentration Zones for Assessing Transportation Project Impacts
• Equity Measures and Their Performance in Transportation
• Estimation of Fuel Use by Idling Commercial Trucks
• Geographic Information System Analysis of Accessibility as Indicator of Potential Land Use Changes and of Induced Impacts on the Environment: Application to the Pyrenean Area of France and Spain
• Hydrogen Delivery Scenario Analysis Model for Hydrogen Distribution Options
• Integrating Information Technology in Efficient Transportation Decision Making: Florida’s Environmental Screening Tool
• Interagency Development of Performance Standards for Managing Materials, Wastes, and Contamination Under Oregon’s Bridge Program: Benefits of Incorporating Environmental Sustainability into Oregon Bridge Construction
• Preservation of Historic Transportation Facilities
• Simplified Analysis Method for Natural Dispersion of Highway Storm Water Runoff in Rural Areas
• Strategy Development of Mixed Land Use for Restraining Trip Generation in Taipei City, Taiwan
• Surface Retexturing to Reduce Tire–Road Noise for Existing Concrete Pavements
• Systems Analysis of Hydrogen Transition with HyTrans
• The Kyoto Protocol and Sustainable Cities: Potential Use of Clean-Development Mechanism in Structuring Cities for Carbon-Efficient Transportation
• Transportation Finance, Congestion, and Equity: Some Policy Perspectives
• Transportation Sector and Supply Chain Performance and Sustainability
• Urban Mobility and Sustainability in Asia and the Power of Context
• Use of Gas Cushions for Field Measurement and Analysis of Hybrid Vibration Isolation Wall