Research funds were provided by a grant from the California Department of Transportation:
Gordon Frankie and Kenneth Hagen, principal investigators. The authors thank Daniel
V. Cassidy, of Caltrans, for support and encouragement.
The contents of this report reflect the views of the authors, who are responsible
for the facts and the accuracy of the data presented herein. The contents do not necessarily
reflect the official views or policies of the State of California or the Federal Highway
Administration. This report does not constitute a standard, specification, or regulation.