Public Roads (ISSN 0033-3735; USPS 516-690) is published quarterly by the Office of Research and Development, Federal Highway Administration (FHWA), 400 Seventh Street SW., Washingiton, DC 20530. Second class postage paid at Washington, DC, and additional mailing offices.

POSTMASTER: Send address changes to Public Roads, HRD-10, FHWA, 6300 Georgetown Pike, McLean, VA 22101-2296

The editorial office of Public Roads is located at the McLean address above. Phone (202) 493-3191. Internet e-mail: [email protected].

Public Roads is sold by the Superintendent of Documents, U.S. Government Printing Office, Washington, DC 20402, for $9.50 per year ($11.90 for foreign mailing). Check or money order should be made payable and sent directly to New Orders, Superintendent of Documents, P.O. Box 371954, Pittsburgh, PA 15250-7954. Subscriptions are available for one-year periods. Paid subscribers should send change of address notices to the U.S. Government Printing Office, Claims Office, Washington, DC 20402.

The Secretary of Transportation has determined that the publication of this periodical is necessary in the transaction of the public business required by law of this Department. All articles are advisory or informational in nature and should not be construed as having regulatory effect.

Articles written by private individuals contain the personal views of the author and do not necessarily reflect those of FHWA. All photographs are provided by FHWA unless otherwise credited.

Contents of this publication may be reprinted provided credit is given to Public Roads and the author.

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NOTICE

The United States Government does not endorse products or manufacturers. Trade or manufacturers' names appear herein solely because they are considered essential to the object of an article.

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