National Academy Press
2101 Constitution Avenue, N.W. Washington, D.C. 20418
NOTICE: The project that is the subject of this report was approved by the Governing Board of the National Research Council, whose members are drawn from the councils of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. The members of the committee responsible for the report were chosen for their special competencies and with regard for appropriate balance.
This report has been reviewed by a group other than the authors according to procedures approved by a Report Review Committee consisting of members of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine.
The National Academy of Sciences is a private, nonprofit, self-perpetuating society of distinguished scholars engaged in scientific and engineering research, dedicated to the furtherance of science and technology and to their use for the general welfare. Upon the authority of the charter granted to it by the Congress in 1863, the Academy has a mandate that requires it to advise the federal government on scientific and technical matters. Dr. Frank Press is president of the National Academy of Sciences.
The National Academy of Engineering was established in 1964, under the charter of the National Academy of Sciences, as a parallel organization of outstanding engineers. It is autonomous in its administration and in the selection of its members, sharing with the National Academy of Sciences the responsibility for advising the federal government. The National Academy of Engineering also sponsors engineering programs aimed at meeting national needs, encourages education and research, and recognizes the superior achievements of engineers. Dr. Robert M. White is president of the National Academy of Engineering.
The Institute of Medicine was established in 1970 by the National Academy of Sciences to secure the services of eminent members of appropriate professions in the examination of policy matters pertaining to the health of the public. The Institute acts under the responsibility given to the National Academy of Sciences by its congressional charter to be an advisor to the federal government and, upon its own initiative, to identify issues of medical care, research, and education. Dr. Kenneth Shine is the president and chairman of the Institute of Medicine.
The National Research Council was organized by the National Academy of Sciences in 1916 to associate the broad community of science and technology with the Academy's purposes of furthering knowledge and advising the federal government. Functioning in accordance with general policies determined by the Academy, the Council has become the principal operating agency of both the National Academy of Sciences and the National Academy of Engineering in providing services to the government, the public, and the scientific and engineering communities. The Council is administered jointly by both Academies and the Institute of Medicine. Dr. Frank Press and Dr. Robert M. White are chairman and vice chairman, respectively, of the National Research Council.
This is a report of work supported by Grant No. DTNH22-91-Z-06014 from the National Highway Traffic Safety Administration and the Federal Highway Administration of the U.S. Department of Transportation to the National Research Council. The work was also supported by the Casey Fund of the National Research Council.
ISBN 0-309-04530-4
Copyright © 1992 by the National Academy of Sciences
Printed in the United States of America
First Printing, April 1992
Second Printing, August 1992
Third Printing, November 1992
COMMITTEE ON FUEL ECONOMY OF AUTOMOBILES AND LIGHT TRUCKS
Chairman
RICHARD A. MESERVE, Partner,
Covington & Burling, Washington, D.C.
Members
GARY L. CASEY, former director,
Advanced Technology, Allied-Signal, Inc., Troy, Michigan
W. ROBERT EPPERLY, President,
Epperly Associates, Inc., New Canaan, Connecticut
THEODORE H. GEBALLE, Professor of Applied Physics,
Department of Applied Physics, Stanford University, Stanford, California
DAVID L. GREENE, Senior Research Staff,
Oak Ridge National Laboratory, Oak Ridge, Tennessee
JOHN H. JOHNSON, Presidential Professor and Chairman,
Department of Mechanical Engineering - Engineering Mechanics, Michigan Technological University, Houghton, Michigan
MARYANN N. KELLER, Managing Director,
Furman Selz Incorporated, New York, New York
CHARLES D. KOLSTAD, Associate Professor,
Institute for Environmental Studies and Department of Economics, University of Illinois, Urbana, Illinois
LEROY H. LINDGREN, Vice President,
Rath & Strong, Inc., Lexington, Massachusetts
G. MURRAY MACKAY, Head,
Accident Research Unit, Automotive Engineering Center, University of Birmingham, Birmingham, England
M. EUGENE MERCHANT, Senior Consultant,
Institute of Advanced Manufacturing Sciences, Cincinnati, Ohio
DAVID L. MORRISON, Technical Director,
Energy, Resource and Environmental Systems Division, The MITRE Corporation, McLean, Virginia
PHILLIP S. MYERS, Emeritus Distinguished Professor of Mechanical Engineering,
University of Wisconsin, Madison, Wisconsin
DANIEL ROOS, Director,
Center for Technology Policy and Industrial Development, Massachusetts Institute of Technology, Cambridge, Massachusetts
PATRICIA F. WALLER, Director,
University of Michigan Transportation Research Institute, University of Michigan, Ann Arbor, Michigan
JOSEPH D. WALTER, Director of Central Research,
Bridgestone-Firestone, Inc., Akron, Ohio
National Research Council Staff
Energy Engineering Board
MAHADEVAN (DEV) MANI, Study Director
CHRISTOPHER T. HILL, Executive Director,
The Manufacturing Forum (on loan)
GEORGE LALOS, Project Manager
JAMES ZUCCHETTO, Senior Program Officer
JUDITH AMRI, Study Administrative Assistant
SUSANNA E. CLARENDON, Administrative Assistant
STEPHEN CARRUTH, Study Assistant (January-June, 1991)
THERESA FISHER, Study Assistant
PENELOPE J. GIBBS, Administrative Assistant,
The Manufacturing Forum (on loan)
PHILOMINA MAMMEN, Study Assistant
NANCY WHITNEY, Study Assistant (January-September, 1991)
JEAN M. SHIRHALL, Consulting Editor
Commission on Engineering and Technical Systems
ARCHIE WOOD, Executive Director
ENERGY ENGINEERING BOARD
Chairman
JOHN A. TILLINGHAST, President,
Tiltec, Portsmouth, New Hampshire
Members
DONALD B. ANTHONY, Vice President and Manager for Technology,
Bechtel Corporation, Houston, Texas
RICHARD E. BALZHISER, President and Chief Executive Officer,
Electric Power Research Institute, Palo Alto, California
BARBARA R. BARKOVICH, Partner,
Barkovich and Yap, Consultants, Berkeley, California
JOHN A. CASAZZA, President,
CSA Energy Consultants, Arlington, Virginia
RALPH C. CAVANAGH, Senior Staff Attorney,
Natural Resources Defense Council, San Francisco, California
DAVID E. COLE, Director,
Center for the Study of Automotive Transportation, University of Michigan, Ann Arbor, Michigan
H. M. (HUB) HUBBARD,
University of Hawaii at Manoa, Honolulu, Hawaii
CHARLES IMBRECHT, Chairman,
California Energy Commission, Sacramento, California
CHARLES D. KOLSTAD, Associate Professor,
Institute for Environmental Studies and Department of Economics, University of Illinois, Urbana, Illinois
HENRY R. LINDEN, Max McGraw Professor of Energy and Power Engineering & Management, and Director,
Energy and Power Center, Illinois Institute of Technology, Chicago, Illinois
S. L. (CY) MEISEL, former Vice President, Research (retired),
Mobile R&D Corporation, Princeton, New Jersey
DAVID L. MORRISON, Technical Director,
Energy, Resource and Environmental Systems Division, The MITRE Corporation, McLean, Virginia
MARC H. ROSS, Professor,
Physics Department, University of Michigan, Ann Arbor, Michigan
MAXINE L. SAVITZ, Managing Director,
Garrett Ceramic Component Division, Torrance, California
HAROLD H. SCHOBERT, Chairman,
Fuel Sciences Program, Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania
GLENN A. SCHURMAN, Vice President, Production (retired),
Chevron Corporation, San Francisco, California
JON M. VEIGEL, President,
Oak Ridge Associated Universities, Oak Ridge, Tennessee
BERTRAM WOLFE, Vice President and General Manager,
General Electric Nuclear Energy Division, San Jose, California
RICHARD WILSON, Mallinckrodt Professor of Physics,
Harvard University, Cambridge, Massachusetts
Liaison Members from the Commission on Engineering and Technical Systems
KENT F. HANSEN, Professor of Nuclear Engineering,
Energy Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts
JOHN B. WACHTMAN, Sosman Professor of Ceramics,
Rutgers University, Piscataway, New Jersey
Energy Engineering Board Staff
MAHADEVAN (DEV) MANI, Director
KAMAL ARAJ, Senior Program Officer
GEORGE LALOS, Senior Program Officer
JAMES ZUCCHETTO, Senior Program Officer
JUDITH AMRI, Administrative and Financial Assistant
SUSANNA CLARENDON, Administrative Assistant
STEPHEN CARRUTH, Research Assistant (January-June, 1991)
THERESA FISHER, Senior Project Assistant
PHILOMINA MAMMEN, Senior Project Assistant
NANCY WHITNEY, Senior Project Assistant (January-September, 1991)
NORMAN HALLER, Consultant
Commission on Engineering and Technical Systems
ARCHIE WOOD, Executive Director
MARLENE BEAUDIN, Associate Executive Director
PREFACE
Following upon the oil embargo imposed by the Organization of Petroleum Exporting Countries (OPEC) in 1973, the U.S. Congress took action to reduce the dependence of the United States on imported petroleum. Because the transportation sector, including in particular the automotive subsector, is one of the main consumers of petroleum, Congress in the Energy Policy and Conservation Act of 1975 required that the automotive manufacturers improve the fuel economy of automobiles and light trucks that are sold in the United States. Congress set a requirement that the corporate average fuel economy (CAFE) of the new-car fleet of each manufacturer achieve 27.5 miles per gallon (mpg) in model year 1985 and thereafter. Congress did not, however, explicitly require continuing improvement of fuel economy after the target established in the act was accomplished.
The Congress and the Executive Branch are now reexamining issues of energy policy that have largely been ignored over the past decade. Because the dependence of the United States on foreign petroleum has grown despite advances in automotive fuel economy, Congress is now considering whether to require further improvements in fuel economy over the coming years. Indeed, the recent Persian Gulf war has shown the fragility of important sources of world petroleum supply and has perhaps reinforced the importance of reducing U.S. vulnerability to supply interruption. Moreover, the growing concern over global warming now provides an impetus for improving efficiency in the use of petroleum in view of the fact that automobiles and light trucks are the source of as much as 15 percent of the greenhouse gases emitted from anthropogenic sources in the United States.
In light of this renewed interest in automotive fuel economy, the U.S. Department of Transportation's National Highway Traffic Safety Administration and Federal Highway Administration requested the National Research Council (NRC) to undertake a study of the potential and prospects for improving the fuel economy of new light-duty vehicles. The NRC appointed the Committee on Fuel Economy of Automobiles and Light Trucks to conduct the study. This report is the result of the committee's deliberations in Phase I of the study.
The committee was asked to provide estimates by vehicle size class of the fuel economy that could "practically" be achieved in new automobiles and light trucks produced for the United States in the next decade. In fulfilling this task, the committee was asked, among other points, to examine the technologies that could contribute to improved fuel economy, to identify the barriers to their introduction, and to consider their costs and benefits. The evaluation was to include consideration of the
effects of current environmental and safety requirements and the consequences of potential new requirements on the consumer and the automotive industry. (The full text of the committee's charge is set out in Appendix A; a description of the committee's membership is set out in Appendix G.)
The committee held its first meeting in Washington, D.C., in May 1991. This was followed by a five-day workshop at the Beckman Center in Irvine, California, in July, at which comprehensive presentations were made to the committee on a variety of relevant topics. Following the Irvine meeting, the committee met monthly through December 1991 to hold its deliberations and write this report. In addition, subgroups on technology, safety, emissions and environment, economic impacts, and standards/regulations were formed; the subgroups collectively held eight additional meetings during the course of the study. A chronology of the committee's work and a list of the many individuals who made presentations to the committee and its various subgroups are provided in Appendix F.
A few points about the committee's conclusions warrant mention at the outset. First, it is important to emphasize the caution with which the committee's estimates should be viewed. An examination of the accuracy of previous estimates of future automotive fuel economy provides a humbling demonstration that even knowledgeable analysts have often missed the mark by wide margins in making such predictions. For example, in the late 1970s, various observers estimated that the fuel economy of the new passenger-car fleet in 1990 would range from about 32 to 40 mpg, whereas a 27.8 mpg fleet average was in fact achieved. Many of the important variables in assessing such matters—for example, the price of gasoline—have not followed the expected path, with the consequence that related estimates, such as automotive fuel economy, have proven unreliable. Moreover, even assessments of the technologies that would be significant have proven erroneous; analysts in the 1950s predicted significant market shares by now for gas turbines, those of the 1960s predicted diesels would be in widespread automotive use, those of the 1970s emphasized rotary engines, and those of the 1980s pointed to turbochargers. The committee does not claim that its crystal ball is any less cloudy than those used by previous analysts; unforeseen events could cause its evaluations to be significantly in error.
Second, and wholly apart from the difficulties of predicting the future, difficulties are presented by reason of the many factors that must be considered in assessing the fuel economy that is practically achievable. As will be explained more fully in this report, the judgment as to what fuel economy gains are practical involves the assessment of a complex manifold of considerations: the perceived severity of the environmental impacts of energy use; the political and economic implications of growing dependence on imported oil; the availability and costs of fuel efficiency technologies; the price of gasoline; the evolution, impacts, and consequences of environmental and safety considerations; the time and capital required for the automotive industry to change its production facilities; the attitudes and interests of consumers; the financial capability of the domestic industry to accommodate new requirements; the consequences of new requirements on automotive workers and suppliers; the differential competitive impacts on foreign and domestic manufacturers;
and many other matters. Unfortunately, most of these considerations do not lend themselves to precise or reliable evaluation.
Third, even if the committee had the capacity to predict the future and to estimate the various relevant factors, the determination of what is practically achievable requires a significant measure of judgment on which reasonable people may disagree. The central theme of this report is that any strategy to increase fuel economy will impose costs and benefits—as will a policy of not encouraging improved fuel economy. Although the committee attempted to estimate the various costs and benefits at least qualitatively, ultimately the policymaker must decide how much enhanced fuel economy is worth. The determination of the appropriate balance of costs and benefits requires a measure and trade-off of values that extend beyond the special competence of this committee.
In light of these facts, the committee aimed in this report to provide information to guide and assist policymakers. In the final analysis, it hopes only that its efforts will be viewed as having defined and illuminated the issues, rather than having finally resolved them.
A few aspects of the study also warrant mention at the outset. Although the committee was charged with examining the fuel economy that is practically achievable over the next decade, it expanded the scope of its evaluation to 2006. As will be explained, over the next four years there is in fact little opportunity to increase fuel economy beyond the levels already planned by the manufacturers. The decade of opportunity for improved fuel economy starts in 1996.
The committee also examined only conventionally powered automobiles and light trucks, that is, those using gasoline and diesel fuel. It did not consider electric or gasoline-electric hybrid vehicles or vehicles powered by alternative fuels (such as methanol, ethanol, or natural gas). Although such vehicles might make a contribution, their evaluation would have expanded the scope of a study that already was daunting in its breadth. Such vehicles might be included in future work.
Although its charge did not require the committee to analyze the current structure and form of fuel economy standards or to address possible alternative approaches to improving fuel economy, the committee concluded that commentary on such matters was appropriate. The means by which enhanced fuel economy is achieved are perhaps as important as the matters the committee was asked to address. Thus, in the committee's opinion, a discussion of such matters is essential to provide perspective on the findings and recommendations requested by its charge. The committee's commentary on policies for improving fuel economy is set out in the concluding chapter. The commentary is by no means definitive because it is limited to an elucidation of the larger context in which fuel economy regulation ought to be considered by policymakers.
It only remains to be said that the committee received very substantial assistance in its efforts from the automotive manufacturers, from industry more generally, from
environmental and safety groups, from the academic community, and from agencies of the U.S. government. The efforts of the many contributors were substantial and lightened the committee's load considerably. Moreover, the committee was assisted by an able, energetic, and enthusiastic staff. The committee appreciates their help.
RICHARD A. MESERVE, Chair
Committee on Fuel Economy of Automobiles and Light Trucks
List of Tables
2-1 |
Illustrative Distribution of the Energy Delivered to the Drive Wheels |
|||
2-2 |
Fuel Economy Technologies for Automobiles and Light Trucks |
|||
3-1 |
Occupant Fatalities in Passenger Vehicles by Vehicle Type, 1990 Fatal Accident Reporting System |
|||
4-1 |
Passenger-Car Emissions Standards, Clean Air Act Amendments of 1990 |
|||
4-2 |
California Passenger-Car Emissions Standards |
|||
5-1 |
Closings and Openings of North American Assembly Plants by the American-Owned Automobile Companies |
|||
6-1 |
Change in Optional Equipment for Selected Model Year Passenger Cars |
|||
7-1 |
Recent Projections of the Average Fuel Economy of Future New Passenger-Car Fleets |
|||
7-2 |
Trend Projections of Fuel Economy of New Passenger Cars |
|||
7-3 |
Trend Projections of Fuel Economy of New Light Trucks |
|||
7-4 |
Best-In-Class Fuel Economy, MY 1990 Passenger Cars |
|||
7-5 |
Best-In-Class Fuel Economy, MY 1990 Light Trucks |
|||
7-6 |
Effect of Performance Reduction on Projected Fuel Economy Levels |
|||
8-1 |
''Technically Achievable" Fuel Economy for MY 2006 Vehicles |
|||
8-2 |
"Technically Achievable" Fuel Economy Levels for MY 1996, MY 2001, and MY 2006 Vehicles by Size-Class and for the New Passenger Car and Light Truck Fleets |
|||
8-3 |
Effects of Technically Achievable Fuel Economy Improvements on Lifetime Fuel Cost Savings: Illustrative Example |
|||
8-4 |
Incremental Retail Prices for Improved Fuel Economy, Improved Occupant Safety, and Tier I Emissions Control in MY 2006 Vehicles (1990 dollars) |
B-1 |
Estimates of Fuel Economy Improvement Potential of Various Technologies |
|||
B-2 |
Costs of Fuel Economy Improvement Technologies |
|||
C-1 |
High Fuel Economy Prototype Vehicles |
|||
D-1 |
Simplified Illustration of Hypothetical Relative Fatality Risks in Two Car Collision |
|||
D-2 |
Hypothetical Relation Collision Frequencies, Base Fleet |
|||
D-3 |
Base Fleet Fatality Indices |
|||
D-4 |
Fatality Consequences of Changes in Fleet Size Mix |
|||
E-1 |
Technologies for Improving the Fuel Economy of Subcompact Cars (based on EEA Data) |
|||
E-2 |
Illustrative Calculations of Fuel Economy Improvements and Incremental Costs of Subcompact Cars Using Shopping Cart Method and Data in Table E-1 |
|||
E-3 |
Technologies for Improving the Fuel Economy of Subcompact Cars (based on SRI Data) |
|||
E-4 |
Illustrative Calculations of Fuel Economy Improvements and Incremental Costs of Subcompact Cars Using Shopping Cart Method and Data in Table E-3 |
List of Figures
1-1 |
Trends in fuel economy for cars and light trucks. |
|||
1-2 |
Trends in average weight for passenger cars sold in the United States, 1975-1991. |
|||
1-3 |
Trends in average interior volume for passenger cars sold in the United States, 1975-1991. |
|||
1-4 |
U.S. crude oil and gasoline prices, 1976-1989. |
|||
1-5 |
Sales fraction by car class. |
1-6 |
Average engine size for passenger cars, 1975-1991. |
|||
1-7 |
Average engine horsepower for passenger cars, 1975-1991. |
|||
1-8 |
The ratio of horsepower to engine displacement for passenger cars, 1975-1990. |
|||
1-9 |
Performance of passenger cars as measured by time to accelerate from 0 to 60 miles per hour, 1975-1991. |
|||
1-10 |
Car and truck sales by size class, 1975-1991. |
|||
1-11 |
U.S. gasoline consumption, 1960-1990. |
|||
2-1 |
Where the energy in the fuel goes. |
|||
2-2 |
Illustrative distribution of energy released in the engine as a function of load. |
|||
2-3 |
Torque curves for various engines. |
|||
3-1 |
Death rate per hundred million vehicle miles. |
|||
5-1 |
Net income of Chrysler, Ford, and General Motors automotive companies, 1980-1990. |
|||
5-2 |
U.S. motor vehicle and equipment manufacturing employment, 1977-1990. |
|||
5-3 |
Net vehicle output (sales of new cars and used cars) per worker in constant 1989 dollars and autos per worker. |
|||
6-1 |
Trends in the sale and scrappage of automobiles and light trucks. |
|||
6-2 |
U.S. population between 16 and 65 years of age, historical and projected, and automobile registrations. |
|||
6-3 |
Family income and new car expenditures in constant 1970 dollars. |
|||
6-4 |
Average monthly payment for new car loans (1989 dollars). |
|||
6-5 |
Hypothetical total car and net present value (NPV) fuel costs. |
|||
6-6 |
Annual vehicle miles traveled (VMT) per passenger car in relation to the price of gasoline (1976-1988). |
|||
6-7 |
Age distribution of the U.S. population, 1987, 2000, 2010, 2030. |
6-8 |
Car buyers by age group. |
|||
7-1 |
Fuel economy trends for the new passenger-car fleet. |
|||
7-2 |
Fuel economy trends for the new light-truck fleet. |
|||
7-3 |
New passenger-car fuel economy by percentile group. |
|||
7-4 |
Shopping cart projection results for subcompact passenger cars. |
|||
7-5 |
Shopping cart projection results for compact passenger cars. |
|||
7-6 |
Shopping cart projection results for midsize passenger cars. |
|||
7-7 |
Shopping cart projection results for large passenger cars. |
|||
7-8 |
Shopping cart projection results for small utility vehicles. |
|||
7-9 |
Shopping cart projection results for small vans. |
|||
7-10 |
Shopping cart projection results for small pickups. |
|||
7-11 |
Shopping cart projection results for large pickups. |
|||
8-1 |
Dependence of fuel consumption on fuel economy for 100,000 vehicle miles traveled. |
|||
8-2 |
Cumulative percentage increase in fuel savings as a function of fuel economy with 27.5 mpg as a base. |
|||
9-1 |
Gasoline prices for selected countries, 1979 and 1989. |
|||
C-1 |
Relationship of fuel consumption to production of oxides of nitrogen in a lean burn engine at various air to fuel ratios with and without exhaust gas recirculation. |
|||
E-1 |
Calculation of fuel economy costs for subcompact cars (data from Table E-2). |
|||
E-2 |
Calculation of fuel economy costs for subcompact cars (data from Table E-4). |