THE NATIONAL ACADEMIES PRESS 500 Fifth Street, NW Washington, DC 20001
NOTICE: This publication has been reviewed according to procedures approved by the National Academy of Engineering report review process. Publication of signed work signifies that it is judged a competent and useful contribution worthy of public consideration, but it does not imply endorsement of conclusions or recommendations by the National Academy of Engineering. The interpretations and conclusions in such publications are those of the authors and do not purport to present the views of the council, officers, or staff of the National Academy of Engineering.
This project was supported by funding from the US Department of Transportation. Any opinions, finding, or conclusions expressed in this publication are those of the workshop participants.
International Standard Book Number 13: 978-0-309-28542-1
International Standard Book Number 10: 0-309-28542-9
Copies of this report are available from the National Academies Press, 500 Fifth Street, NW, Keck 360, Washington, DC 20001; (888) 624-8373 or (202) 334-3313; www.nap.edu.
For more information about the National Academy of Engineering, visit the NAE home page at www.nae.edu.
Copyright 2013 by the National Academies. All rights reserved.
Printed in the United States of America