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http://onlinepubs.trb.org...s/trr/1983/898/898-034.pdf

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The low-water crossing structure (LWCS) frequently represents a significant financial saving, although these structures may be overtopped and damaged by floods. Thus decisionmakers are hesitant to build them. Currently, there is no guide on the selection of the LWCS. Consequently, a public opinion survey was conducted and the results are presented to serve as a useful guide for the selection of the type of structure to build. About 60 responses (36 detailed, 24 brief) from the United States and 3 responses from Canada were received and analyzed. The most important tangible factors (in order of importance) are possible damage to human life, average daily traffic (ADT), frequency of possible flooding, legal considerations, and location as part of an emergency route. Availability of an alternate route, duration of traffic interruptions, and possible property damage form the second important group of factors. There is no difference of opinion among different regions of the country. For a 28 percent saving of total tangible costs, decisionmakers would consider the LWCS. The desirable conditions are less than 5 ADT, average annual flooding frequency less than 2, good hydrologic analysis, average duration of traffic interruption less than 24 h, not more than 60 min of travel by alternate route, chance of having a human life involved less than 1 in 1 billion, and an excellent warning system. A set of absolute constraints below which no LWCS would be considered was also obtained. It must be emphasized that each decisionmaker must use his or her judgment to decide on which type of structure to build for each location, and there can never be any rigid rule to be followed. Ultimately, the decisionmaker must evaluate all the tangible and intangible factors involved for a given case to make the selection of the structure to build. The method must be chosen, the analysis conducted, and the decision made. Defense of the decision may also be required. (Author)

Publication of this paper sponsored by Committee on Low-Volume Roads. Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved

00380954

N908

pp 221-227

1983

Transportation Research Record

Third International Conference on Low-Volume Roads

0309035112

Print

Figures (1) ; References (6) ; Tables (4)

Average daily traffic; Causeways; Design; Fatalities; Floods; Hazards; Public opinion; Risk assessment

Design criteria; Flood frequency; Selecting

Bridges and other structures; Design; Economics; Highways; Hydraulics and Hydrology; Safety and Human Factors; Society; I24: Design of Bridges and Retaining Walls

TRIS, TRB

Aug 30 1983 12:00AM