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Suggested Citation:"Front Matter." National Academies of Sciences, Engineering, and Medicine. 2021. Assessment of Technologies for Improving Light-Duty Vehicle Fuel Economy—2025-2035. Washington, DC: The National Academies Press. doi: 10.17226/26092.
×

ASSESSMENT OF TECHNOLOGIES FOR

Improving Light-Duty Vehicle
Fuel Economy—2025-2035

Committee on Assessment of Technologies for Improving Fuel Economy
of Light-Duty Vehicles—Phase 3

Board on Energy and Environmental Systems

Division on Engineering and Physical Sciences

A Consensus Study Report of

images

THE NATIONAL ACADEMIES PRESS
Washington, DC
www.nap.edu

Suggested Citation:"Front Matter." National Academies of Sciences, Engineering, and Medicine. 2021. Assessment of Technologies for Improving Light-Duty Vehicle Fuel Economy—2025-2035. Washington, DC: The National Academies Press. doi: 10.17226/26092.
×

THE NATIONAL ACADEMIES PRESS 500 Fifth Street, NW Washington, DC 20001

This activity was supported by Award No. DTNH2217H00028 of the U.S. Department of Transportation and National Highway Traffic Safety Administration. Any opinions, findings, conclusions, or recommendations expressed in this publication do not necessarily reflect the views of any organization or agency that provided support for the project.

International Standard Book Number-13: 978-0-309-37122-3
International Standard Book Number-10: 0-309-37122-8
Digital Object Identifier: https://doi.org/10.17226/26092
Library of Congress Control Number: 2021951949

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Suggested citation: National Academies of Sciences, Engineering, and Medicine. 2021. Assessment of Technologies for Improving Light-Duty Vehicle Fuel Economy—2025–2035. Washington, DC: The National Academies Press. https://doi.org/10.17226/26092.

Suggested Citation:"Front Matter." National Academies of Sciences, Engineering, and Medicine. 2021. Assessment of Technologies for Improving Light-Duty Vehicle Fuel Economy—2025-2035. Washington, DC: The National Academies Press. doi: 10.17226/26092.
×

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The National Academy of Sciences was established in 1863 by an Act of Congress, signed by President Lincoln, as a private, nongovernmental institution to advise the nation on issues related to science and technology. Members are elected by their peers for outstanding contributions to research. Dr. Marcia McNutt is president.

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Learn more about the National Academies of Sciences, Engineering, and Medicine at www.nationalacademies.org.

Suggested Citation:"Front Matter." National Academies of Sciences, Engineering, and Medicine. 2021. Assessment of Technologies for Improving Light-Duty Vehicle Fuel Economy—2025-2035. Washington, DC: The National Academies Press. doi: 10.17226/26092.
×

Image

Consensus Study Reports published by the National Academies of Sciences, Engineering, and Medicine document the evidence-based consensus on the study’s statement of task by an authoring committee of experts. Reports typically include findings, conclusions, and recommendations based on information gathered by the committee and the committee’s deliberations. Each report has been subjected to a rigorous and independent peer-review process and it represents the position of the National Academies on the statement of task.

Proceedings published by the National Academies of Sciences, Engineering, and Medicine chronicle the presentations and discussions at a workshop, symposium, or other event convened by the National Academies. The statements and opinions contained in proceedings are those of the participants and are not endorsed by other participants, the planning committee, or the National Academies.

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Suggested Citation:"Front Matter." National Academies of Sciences, Engineering, and Medicine. 2021. Assessment of Technologies for Improving Light-Duty Vehicle Fuel Economy—2025-2035. Washington, DC: The National Academies Press. doi: 10.17226/26092.
×

COMMITTEE ON ASSESSMENT OF TECHNOLOGIES FOR IMPROVING FUEL ECONOMY OF LIGHT-DUTY VEHICLES—PHASE 3

GARY MARCHANT, Arizona State University, Chair

CARLA BAILO, Center for Automotive Research

RODICA BARANESCU, NAE,1 University of Illinois, Chicago (retired) (resigned September 2020)

NADY BOULES, NB Motors, LLC

DAVID L. GREENE, University of Tennessee, Knoxville (resigned March 2021)

DANIEL KAPP, D.R. Kapp Consulting, LLC

ULRICH KRANZ, Canoo

THERESE LANGER, American Council for an Energy-Efficient Economy

ZHENHONG LIN, Oak Ridge National Laboratory

JOSHUA LINN, University of Maryland, College Park

NIC LUTSEY, International Council on Clean Transportation

JOANN MILLIKEN, Independent Consultant, Alexandria, Virginia

RANDA RADWAN, Highway Safety Research Center, University of North Carolina, Chapel Hill

ANNA STEFANOPOULOU, University of Michigan and Automotive Research Center

DEIDRE STRAND, Wildcat Discovery Technologies

KATE WHITEFOOT, Carnegie Mellon University

Staff

ELIZABETH ZEITLER, Associate Director, Board on Energy and Environmental Systems (BEES), Study Director

REBECCA DeBOER, Research Assistant, BEES

BRENT HEARD, Associate Program Officer, BEES (beginning January 2020)

K. JOHN HOLMES, Director/Scholar, BEES

MICHAELA KERXHALLI-KLEINFIELD, Research Associate, BEES

KASIA KORNECKI, Associate Program Officer, BEES (beginning February 2020)

KATHERINE KORTUM, Senior Program Officer, Transportation Research Board

HEATHER LOZOWSKI, Senior Financial Business Partner, BEES

BEN WENDER, Senior Program Officer, BEES (until December 2019)

CATHERINE WISE, Associate Program Officer, BEES (beginning June 2020)

NOTE: See Appendix B, Disclosure of Conflicts of Interest.

___________________

1 Member, National Academy of Engineering.

Suggested Citation:"Front Matter." National Academies of Sciences, Engineering, and Medicine. 2021. Assessment of Technologies for Improving Light-Duty Vehicle Fuel Economy—2025-2035. Washington, DC: The National Academies Press. doi: 10.17226/26092.
×

BOARD ON ENERGY AND ENVIRONMENTAL SYSTEMS

JARED COHON, NAE,1 Carnegie Mellon University, Chair

VICKY BAILEY, Anderson Stratton Enterprises

CARLA BAILO, Center for Automotive Research

W. TERRY BOSTON, NAE, GridLiance GP, LLC, and Grid Protection Alliance

DEEPAKRAJ DIVAN, NAE, Georgia Institute of Technology

MARCIUS EXTAVOUR, XPRIZE

KELLY SIMS GALLAGHER, Tufts University

TJ GLAUTHIER, TJG Energy Associates, LLC

NAT GOLDHABER, Claremont Creek Ventures

DENISE GRAY, LG Chem Michigan, Inc.

JOHN KASSAKIAN, NAE, Massachusetts Institute of Technology

BARBARA KATES-GARNICK, Tufts University

DOROTHY ROBYN, Boston University

JOSÉ SANTIESTEBAN, NAE, ExxonMobil Research and Engineering Company

ALEXANDER SLOCUM, NAE, Massachusetts Institute of Technology

JOHN WALL, NAE, Cummins, Inc. (retired)

ROBERT WEISENMILLER, California Energy Commission (former)

Staff

K. JOHN HOLMES, Director/Scholar

ELIZABETH ZEITLER, Associate Director

HEATHER LOZOWSKI, Senior Financial Business Partner

BEN WENDER, Senior Program Officer (until December 2019)

BRENT HEARD, Associate Program Officer (beginning January 2020)

KASIA KORNECKI, Associate Program Officer (beginning February 2020)

CATHERINE WISE, Associate Program Officer (beginning June 2020)

MICHAELA KERXHALLI-KLEINFIELD, Research Associate

REBECCA DeBOER, Research Assistant

___________________

1 Member, National Academy of Engineering.

Suggested Citation:"Front Matter." National Academies of Sciences, Engineering, and Medicine. 2021. Assessment of Technologies for Improving Light-Duty Vehicle Fuel Economy—2025-2035. Washington, DC: The National Academies Press. doi: 10.17226/26092.
×

Preface

Passenger car and truck manufacturers have faced corporate average fuel economy standards since 1978 and greenhouse gas emissions standards since 2012, governed by several statutes and specified in regulations from the U.S. Department of Transportation’s National Highway Traffic Safety Administration (NHTSA) and the U.S. Environmental Protection Agency (EPA). Over this period, vehicle efficiency technology has advanced dramatically, including improvements to internal combustion engine powertrains; introductions of efficient hybrid, electric, and fuel cell vehicles; improvements to vehicle aerodynamics and mass reduction technologies; and introduction of limited vehicle automation. NHTSA and EPA have increasingly incorporated technology analysis into estimate costs and benefits of fuel economy and greenhouse gas standards. Beginning in 2007, Congress requested that the National Academies of Sciences, Engineering, and Medicine undertake periodic review of technologies for fuel economy standards. Most recently, NHTSA contracted with the National Academies to form the Committee on Assessment of Technologies for Improving Fuel Economy of Light-Duty Vehicles—Phase 3 to update the requested technology, consumer behavior, and policy analysis of vehicle efficiency technologies for 2025–2035.

The committee was asked to assess technologies for improving the fuel economy of light-duty vehicles in 2025–2035 and to provide updated estimates of the potential cost, fuel economy improvements, and barriers to deployment of these technologies. The committee was asked to consider internal combustion engine, electric, and fuel cell propulsion systems; non-powertrain technologies; the structure of the fuel economy regulations related to new technologies; shifts in personal transportation and vehicle ownership models; and consumer behavior associated with new efficiency technologies.

The committee comprised a wide array of backgrounds and sought input from agency officials, vehicle manufacturers, equipment suppliers, consultants, nongovernmental organizations, academicians, and many other experts. In addition to regular committee meetings, committee members held webinars on several critical topics, spoke in public sessions with experts in state and federal government, and conducted numerous information-gathering site visits to automobile manufacturers and suppliers. The committee put great effort into thorough preparation for these meetings, asked probing questions, and requested follow-up information in order to understand the perspectives of the many stakeholders. In addition, the committee commissioned a material substitution and mass reduction study from the Center for Automotive Research in order to better understand the opportunities for these advances. I greatly appreciate the considerable time and effort contributed by the committee’s individual members throughout our information-gathering process, report writing, and deliberations, and especially for persevering through the challenges presented by the COVID-19 pandemic during the important final stages of completing our report.

Page viii Cite
Suggested Citation:"Front Matter." National Academies of Sciences, Engineering, and Medicine. 2021. Assessment of Technologies for Improving Light-Duty Vehicle Fuel Economy—2025-2035. Washington, DC: The National Academies Press. doi: 10.17226/26092.
×

The committee operated under the auspices of the National Academies Board on Energy and Environmental Systems, in collaboration with the Transportation Research Board. I would like to recognize the study staff for organizing and planning meetings, and assisting with information gathering and report development. The efforts of our hardworking and knowledgeable study director Elizabeth Zeitler, ably assisted by her National Academies colleagues Rebecca DeBoer, Michaela Kerxhalli-Kleinfield, Brent Heard, Kasia Kornecki, Catherine Wise, K. John Holmes, and Katherine Kortum, were critical to the committee’s delivery of its report. I would also like to recognize Ben Wender and Janki Patel for their early input. Thanks are also due to the many experts and presenters, too numerous to name individually, who contributed to the committee’s data-gathering process. Their contributions were invaluable and are listed in Appendix C.

Gary Marchant,
Chair, Committee on Assessment of Technologies
for Improving Fuel Economy of Light-Duty Vehicles—Phase 3

Suggested Citation:"Front Matter." National Academies of Sciences, Engineering, and Medicine. 2021. Assessment of Technologies for Improving Light-Duty Vehicle Fuel Economy—2025-2035. Washington, DC: The National Academies Press. doi: 10.17226/26092.
×

Acknowledgment of Reviewers

This Consensus Study Report was reviewed in draft form by individuals chosen for their diverse perspectives and technical expertise. The purpose of this independent review is to provide candid and critical comments that will assist the National Academies of Sciences, Engineering, and Medicine in making each published report as sound as possible and to ensure that it meets the institutional standards for quality, objectivity, evidence, and responsiveness to the study charge. The review comments and draft manuscript remain confidential to protect the integrity of the deliberative process.

We thank the following individuals for their review of this report:

Although the reviewers listed above provided many constructive comments and suggestions, they were not asked to endorse the conclusions or recommendations of this report nor did they see the final draft before its release. The review of this report was overseen by Susan Hanson, Clark University, and Andrew Brown Jr., Diamond Consulting, Engineering, and Management Services. They were responsible for making certain that an independent examination of this report was carried out in accordance with the standards of the National Academies and that all review comments were carefully considered. Responsibility for the final content rests entirely with the authoring committee and the National Academies.

___________________

1 Member, National Academy of Sciences.

2 Member, National Academy of Engineering.

Suggested Citation:"Front Matter." National Academies of Sciences, Engineering, and Medicine. 2021. Assessment of Technologies for Improving Light-Duty Vehicle Fuel Economy—2025-2035. Washington, DC: The National Academies Press. doi: 10.17226/26092.
×

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Suggested Citation:"Front Matter." National Academies of Sciences, Engineering, and Medicine. 2021. Assessment of Technologies for Improving Light-Duty Vehicle Fuel Economy—2025-2035. Washington, DC: The National Academies Press. doi: 10.17226/26092.
×
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Suggested Citation:"Front Matter." National Academies of Sciences, Engineering, and Medicine. 2021. Assessment of Technologies for Improving Light-Duty Vehicle Fuel Economy—2025-2035. Washington, DC: The National Academies Press. doi: 10.17226/26092.
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9.6 Combined Energy Impacts of Autonomous Vehicles

9.7 Autonomous Vehicles and Energy Use: Policy Issues

9.8 Findings and Recommendations

9.9 References

10 ENERGY AND EMISSIONS IMPACTS OF NON-PETROLEUM FUELS IN LIGHT-DUTY VEHICLE PROPULSION

10.1 Introduction

10.2 Electricity, Hydrogen, and Low-Carbon Synthetic Fuels

10.3 Low-Carbon Fuels in the 2025–2035 Fleet

10.4 Recommendations for Non-Petroleum Fuels

10.5 References

11 CONSUMER ACCEPTANCE AND MARKET RESPONSE TO STANDARDS

11.1 Historical Market Trends

11.2 Fuel Economy and Vehicle Travel: Rebound Effects

11.3 How Much Do Consumers Value Fuel Cost Savings and What Are the Implications for Benefit-Cost Analysis?

11.4 Transitions to New Technology

11.5 Role of EV Incentives, Impact of Incentive Expiration, and Whether to Continue EV Incentives

11.6 References

12 REGULATORY STRUCTURE AND FLEXIBILITIES

12.1 History of Vehicle Fuel Economy Regulation

12.2 Measuring Fuel Economy and GHG Emissions

12.3 Regulatory Flexibilities

12.4 International Context of Regulatory Environment

12.5 Fuel Economy Regulation in a Warming World

12.6 References

13 EMERGENT FINDINGS, RECOMMENDATIONS, AND FUTURE POLICY SCENARIOS FOR CONTINUED REDUCTION IN ENERGY USE AND EMISSIONS OF LIGHT-DUTY VEHICLES

13.1 Emergent Findings and Recommendations

13.2 Big Picture: Rethinking Regulation of Fuel Economy in 2025–2035 and Beyond

13.3 References

APPENDIXES

A Committee Biographical Information

B Disclosure of Conflicts of Interest

C Committee Activities

D Acronyms

E Center for Automotive Research Commissioned Study

Suggested Citation:"Front Matter." National Academies of Sciences, Engineering, and Medicine. 2021. Assessment of Technologies for Improving Light-Duty Vehicle Fuel Economy—2025-2035. Washington, DC: The National Academies Press. doi: 10.17226/26092.
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Suggested Citation:"Front Matter." National Academies of Sciences, Engineering, and Medicine. 2021. Assessment of Technologies for Improving Light-Duty Vehicle Fuel Economy—2025-2035. Washington, DC: The National Academies Press. doi: 10.17226/26092.
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Suggested Citation:"Front Matter." National Academies of Sciences, Engineering, and Medicine. 2021. Assessment of Technologies for Improving Light-Duty Vehicle Fuel Economy—2025-2035. Washington, DC: The National Academies Press. doi: 10.17226/26092.
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Suggested Citation:"Front Matter." National Academies of Sciences, Engineering, and Medicine. 2021. Assessment of Technologies for Improving Light-Duty Vehicle Fuel Economy—2025-2035. Washington, DC: The National Academies Press. doi: 10.17226/26092.
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From daily commutes to cross-country road trips, millions of light-duty vehicles are on the road every day. The transportation sector is one of the United States’ largest sources of greenhouse gas emissions, and fuel is an important cost for drivers. The period from 2025-2035 could bring the most fundamental transformation in the 100-plus year history of the automobile. Battery electric vehicle costs are likely to fall and reach parity with internal combustion engine vehicles. New generations of fuel cell vehicles will be produced. Connected and automated vehicle technologies will become more common, including likely deployment of some fully automated vehicles. These new categories of vehicles will for the first time assume a major portion of new vehicle sales, while internal combustion engine vehicles with improved powertrain, design, and aerodynamics will continue to be an important part of new vehicle sales and fuel economy improvement.

This study is a technical evaluation of the potential for internal combustion engine, hybrid, battery electric, fuel cell, nonpowertrain, and connected and automated vehicle technologies to contribute to efficiency in 2025-2035. In addition to making findings and recommendations related to technology cost and capabilities, Assessment of Technologies for Improving Light-Duty Vehicle Fuel Economy - 2025-2035 considers the impacts of changes in consumer behavior and regulatory regimes.

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