GOVERNORS HIGHWAY SAFETY ASSOCIATION RESEARCH COMMITTEE*

CO-CHAIRS

Karson James

Wyoming Department of Transportation

Tim Kerns

Maryland Motor Vehicle Administration

MEMBERS

Rick Birt

District of Columbia Highway Safety Office

Amy Boggs

West Virginia Governor’s Highway Safety Program

Joel Brisson

Tennessee Highway Safety Office

Mark Ezzell

North Carolina Governor’s Highway Safety Program

Brian Harmon

Minnesota Department of Public Safety

Lissette Morgan

Arizona Governor’s Office of Highway Safety

Flavia Pereira

Connecticut Department of Transportation

Max Tyler Roberts

Washington Traffic Safety Commission

TRANSPORTATION RESEARCH BOARD 2025 EXECUTIVE COMMITTEE*

OFFICERS

CHAIR: Leslie S. Richards, General Manager, Southeastern Pennsylvania Transportation Authority (SEPTA), Philadelphia

VICE CHAIR: Joel M. Jundt, Secretary of Transportation, South Dakota Department of Transportation, Pierre

EXECUTIVE DIRECTOR: Victoria Sheehan, Transportation Research Board, Washington, DC

MEMBERS

James F. Albaugh, President and CEO, The Boeing Company (retired), Scottsdale, AZ

Carlos M. Braceras, Executive Director, Utah Department of Transportation, Salt Lake City

Douglas C. Ceva, Vice President, Customer Lead Solutions, Prologis, Inc., Jupiter, FL

Nancy Daubenberger, Commissioner of Transportation, Minnesota Department of Transportation, St. Paul

Marie Therese Dominguez, Commissioner, New York State Department of Transportation, Albany

Garrett Eucalitto, Commissioner, Connecticut Department of Transportation, Newington

Andrew Fremier, Executive Director, Metropolitan Transportation Commission, San Francisco, CA

Martha Grabowski, Professor Emerita, Information Systems, Le Moyne College, Madden College of Business & Economics, Cazenovia, NY

Randell Iwasaki, President and CEO, Iwasaki Consulting Services, Walnut Creek, CA

Carol A. Lewis, Professor, Transportation Studies, Texas Southern University, Houston

Hani S. Mahmassani, W.A. Patterson Distinguished Chair in Transportation; Director, Transportation Center, Northwestern University, Evanston, IL

Scott C. Marler, Director, Iowa Department of Transportation, Ames

Ricardo Martinez, Adjunct Professor of Emergency Medicine, Emory University School of Medicine, Decatur, GA

Russell McMurry, Commissioner, Georgia Department of Transportation, Atlanta

Craig E. Philip, Research Professor and Director, VECTOR, Department of Civil and Environmental Engineering, Vanderbilt University, Nashville, TN

Steward T.A. Pickett, Distinguished Senior Scientist, Cary Institute of Ecosystem Studies, Millbrook, NY

Susan A. Shaheen, Professor and Co-Director, Transportation Sustainability Research Center, University of California, Berkeley

Marc Williams, Executive Director, Texas Department of Transportation, Austin

EX OFFICIO MEMBERS

Michael R. Berube, Deputy Assistant Secretary for Sustainable Transportation, U.S. Department of Energy, Washington, DC

Steven Cliff, Executive Officer, California Air Resources Board, Sacramento

LeRoy Gishi, Chief, Division of Transportation, Bureau of Indian Affairs, U.S. Department of the Interior, Germantown, MD

Firas Ibrahim, Director, Office of Research, Development, and Technology, Office of the Assistant Secretary for Research and Technology (OST-R), Washington, DC

Jason Kelly, Deputy Commanding General for Civil Works and Emergency Operations, U.S. Army Corps of Engineers, Washington, DC

Sandra Knight, President, WaterWonks, LLC, Washington, DC

Zahra “Niloo” Parvinashtiani, Engineer, Mobility Consultant Solutions, Iteris Inc., Fairfax, VA, and Chair, TRB Young Members Coordinating Council

Chris Rocheleau, Acting Administrator, Federal Aviation Administration, Washington, DC

Gloria Shepherd, Acting Deputy Administrator, Federal Highway Administration, Washington, DC

Karl Simon, Director, Transportation and Climate Division, U.S. Environmental Protection Agency, Washington, DC

Paul P. Skoutelas, President and CEO, American Public Transportation Association, Washington, DC

Jim Tymon, Executive Director, American Association of State Highway and Transportation Officials, Washington, DC

___________________

^* Membership as of February 2025.

^* Membership as of February 2025.

BEHAVIORAL TRAFFIC SAFETY COOPERATIVE RESEARCH PROGRAM

Outcomes of Variability in Teen Driving Experience and Exposure

EVIDENCE FROM NATURALISTIC DRIVING STUDIES

Sheila Klauer
Lesheng Hua
Shu Han
Feng Guo
VIRGINIA POLYTECHNIC INSTITUTE AND STATE UNIVERSITY
Blacksburg, VA

Johnathon Ehsani
Michelle Duren
JOHNS HOPKINS UNIVERSITY
Baltimore, MD

Loren Staplin
Tia Mastromatto
TRANSANALYTICS, LLC
Quakertown, PA

Subscriber Categories
Safety and Human Factors

Research sponsored by the Governors Highway Safety Association and National Highway Traffic Safety Administration

BEHAVIORAL TRAFFIC SAFETY COOPERATIVE RESEARCH PROGRAM

Since the widespread introduction of motor vehicles more than a century ago, crashes involving their operation remain a significant public health concern. While there have been enormous improvements in highway design and construction, as well as motor vehicle safety, which have been instrumental in lowering the rate of crashes per million miles in the United States, more than 35,000 people die every year in motor vehicle crashes. In far too many cases, the root causes of the crashes are the unsafe behaviors of motor vehicle operators, cyclists, and pedestrians. Understanding human behaviors and developing effective countermeasures to unsafe ones is difficult and remains a major weakness in our traffic safety efforts.

The Behavioral Traffic Safety Cooperative Research Program (BTSCRP) develops practical solutions to save lives, prevent injuries, and reduce costs of road traffic crashes associated with unsafe behaviors. BTSCRP is a forum for coordinated and collaborative research efforts. It is managed by the Transportation Research Board (TRB) under the direction and oversight of the Governors Highway Safety Association (GHSA) with funding provided by the National Highway Traffic Safety Administration (NHTSA). Funding for the program was originally established in Moving Ahead for Progress in the 21st Century (MAP-21), Subsection 402(c), which created the National Cooperative Research and Evaluation Program (NCREP). Fixing America’s Surface Transportation (FAST) Act continued the program. In 2017, GHSA entered into an agreement with TRB to manage the research activities, with the program name changed to Behavioral Traffic Safety Cooperative Research Program. The GHSA Executive Board serves as the governing board for the BTSCRP. The Board consists of officers, representatives of the 10 NHTSA regions, and committee and task force chairs. The Research Committee Chair appoints committee members who recommend projects for funding and provide oversight for the activities of BTSCRP. Its ultimate goal is to oversee a quality research program that is committed to addressing research issues facing State Highway Safety Offices. The Executive Board meets annually to approve research projects. Each selected project is assigned to a panel, appointed by TRB, which provides technical guidance and counsel throughout the life of the project. The majority of panel members represent the intended users of the research projects and have an important role in helping to implement the results. BTSCRP produces a series of research reports and other products such as guidebooks for practitioners. Primary emphasis is placed on disseminating BTSCRP results to the intended users of the research: State Highway Safety Offices and their constituents.

BTSCRP RESEARCH REPORT 13

Project BTS-23
ISSN 2766-5976 (Print)
ISSN 2766-5984 (Online)
ISBN 978-0-309-72312-1
Library of Congress Control Number 2025933894
Digital Object Identifier: https://doi.org/10.17226/29066

© 2025 by the National Academy of Sciences. National Academies of Sciences, Engineering, and Medicine and the graphical logo are trademarks of the National Academy of Sciences. All rights reserved.

COPYRIGHT INFORMATION

Authors herein are responsible for the authenticity of their materials and for obtaining written permissions from publishers or persons who own the copyright to any previously published or copyrighted material used herein.

Cooperative Research Programs (CRP) grants permission to reproduce material in this publication for classroom and not-for-profit purposes. Permission is given with the understanding that none of the material will be used to imply TRB, AASHTO, APTA, FAA, FHWA, FTA, GHSA, or NHTSA endorsement of a particular product, method, or practice. It is expected that those reproducing the material in this document for educational and not-for-profit uses will give appropriate acknowledgment of the source of any reprinted or reproduced material. For other uses of the material, request permission from CRP.

NOTICE

The research report was reviewed by the technical panel and accepted for publication according to procedures established and overseen by the Transportation Research Board and approved by the National Academies of Sciences, Engineering, and Medicine.

The opinions and conclusions expressed or implied in this report are those of the researchers who performed the research and are not necessarily those of the Transportation Research Board; the National Academies of Sciences, Engineering, and Medicine; or the program sponsors.

The Transportation Research Board does not develop, issue, or publish standards or specifications. The Transportation Research Board manages applied research projects which provide the scientific foundation that may be used by Transportation Research Board sponsors, industry associations, or other organizations as the basis for revised practices, procedures, or specifications.

The Transportation Research Board; the National Academies of Sciences, Engineering, and Medicine; and the sponsors of the Behavioral Traffic Safety Cooperative Research Program do not endorse products or manufacturers. Trade or manufacturers’ names or logos appear herein solely because they are considered essential to the object of the report.

Published research reports of the

BEHAVIORAL TRAFFIC SAFETY COOPERATIVE RESEARCH PROGRAM

are available from

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The National Academy of Engineering was established in 1964 under the charter of the National Academy of Sciences to bring the practices of engineering to advising the nation. Members are elected by their peers for extraordinary contributions to engineering. Dr. John L. Anderson is president.

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

The Transportation Research Board is one of seven major program divisions of the National Academies of Sciences, Engineering, and Medicine. The mission of the Transportation Research Board is to mobilize expertise, experience, and knowledge to anticipate and solve complex transportation-related challenges. The Board’s varied activities annually engage about 8,500 engineers, scientists, and other transportation researchers and practitioners from the public and private sectors and academia, all of whom contribute their expertise in the public interest. The program is supported by state departments of transportation, federal agencies including the component administrations of the U.S. Department of Transportation, and other organizations and individuals interested in the development of transportation.

Learn more about the Transportation Research Board at www.TRB.org.

COOPERATIVE RESEARCH PROGRAMS

CRP STAFF FOR BTSCRP RESEARCH REPORT 13

Monique R. Evans, Director, Cooperative Research Programs

Waseem Dekelbab, Deputy Director, Cooperative Research Programs

Richard A. Retting, Senior Program Officer

Tijhuana Stapleton, Senior Program Assistant

Natalie Barnes, Director of Publications

Heather DiAngelis, Associate Director of Publications

Ellen M. Chafee, Senior Editor

BTSCRP PROJECT BTS-23 PANEL

Federico E. Vaca, University of California, Irvine, Orange, CA (Chair)

Bayliss J. Camp, California Department of Motor Vehicles, Sacramento, CA

Pnina Gershon, Massachusetts Institute of Technology, Cambridge, MA

Min-Wook Kang, University of South Alabama, Mobile, AL

Elisabeta Mitran, Louisiana Transportation Research Center (LTRC), Baton Rouge, LA

Phil Riley, South Carolina Department of Public Safety: Office of Highway Safety and Justice Programs, Blythewood, SC

Alyssa Ryan, University of Arizona, Tucson, AZ

Maria E. Vegega, Road Safety Consulting, Alexandria, VA

Christine Watson, NHTSA Liaison

Bernardo B. Kleiner, TRB Liaison

AUTHOR ACKNOWLEDGMENTS

The research reported herein was performed under BTSCRP Project BTS-23 by the Virginia Tech Transportation Institute (VTTI) with support from Johns Hopkins University (JHU) and TransAnalytics, LLC. Dr. Sheila “Charlie” Klauer, Research Scientist within the Division of Vehicle, Driver & System Safety, was the Project Director and Principal Investigator. The other VTTI authors of this report are Dr. Lesheng Hua, Dr. Shu Han, and Dr. Feng Guo. The JHU investigators included Dr. Johnathon Ehsani, Co-Investigator, and Dr. Michelle Duren. The TransAnalytics investigators included Co-Investigator Dr. Loren Staplin and Tia Mastromatto.

FOREWORD

By Richard A. Retting
Staff Officer
Transportation Research Board

BTSCRP Research Report 13 provides insights on how exposure to driving during the learner’s permit period and the first months of driving independently, including driving in diverse environments, impacts safety outcomes in later driving. The research team used naturalistic driving study data to evaluate how driving exposure and driving in diverse traffic and road environments are associated with teen driver behavior. The researchers also examined how different levels of supervised practice driving relate to teen driver behaviors and their association with safety outcomes and performance variations. This report will be of interest to State Highway Safety Offices (SHSOs) and other stakeholders concerned with young driver safety.

Motor vehicle crash rates for teen drivers during the learner’s permit phase are relatively low and comparable to those of adult drivers. However, once teenagers begin driving independently, the crash risk increases significantly at licensure and remains high during the first few months of solo driving. Due to a lack of definitive scientific evidence, it remains unclear whether teen drivers who are exposed to a greater variety of traffic and road conditions early in their driving experience have a lower likelihood of crash involvement compared to those with less exposure.

Under BTSCRP Project BTS-23, “Outcomes of Variability in Teen Driving Experience and Exposure: Evidence from the Naturalistic Driving Study,” Virginia Polytechnic Institute and State University was asked to (1) evaluate how exposure to driving and driving in diverse environments during early driving impact safety outcomes later in driving for teen drivers, (2) investigate whether driver behaviors are differentially associated with safety outcomes and performance differences given different levels of supervised practice driving, and (3) develop recommendations and strategies for improving teen driver safety for SHSOs.

In addition to BTSCRP Research Report 13, the following deliverables are available on the National Academies Press website (nap.nationalacademies.org) by searching on BTSCRP Research Report 13:

• Technical memorandum on implementation of research findings and products.
• PowerPoint presentation on the conduct of the research.

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CONTENTS

Summary

Chapter 1 Background

Chapter 2 Research Approach

Description of the SHRP 2 NDS

Description of the SPDS NDS

Institutional Review Board and Data Use License Process

Overview of Data Reduction

Study Design

Chapter 3 Results

Descriptive Analysis of Exposure

Summary Data

Research Objective 1a

Research Objective 1b

Research Objective 2

Summary of Findings

Chapter 4 Conclusions and Suggested Research

Conclusions

Suggested Research

Limitations

References

Appendix Supporting Tables

Acronyms and Abbreviations

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