TRAFFIC-SAFE AND HYDRAULICALLY EFFICIENT DRAINAGE PRACTICE

A SYNTHESIS IS PRESENTED OF MEASURES THAT HAVE BEEN FOUND MOST SUCCESSFUL IN MINIMIZING THE ADVERSE SAFETY FEATURES OF DRAINAGE STRUCTURES WHILE MAINTAINING THE HYDRAULIC EFFICIENCY. CURRENT PRACTICES, PLANS, SPECIFICATIONS, MANUALS, AND RESEARCH RECOMMENDATIONS ASSEMBLED FROM THE KNOWLEDGE OF HIGHWAY DEPARTMENTS WERE ANALYZED TO DEVELOP THE SYNTHESIS. A LITERATURE SEARCH WAS MADE OF ALL PERTINENT PUBLICATIONS, INTERVIEWS WERE HELD WITH HIGHWAY PERSONNEL, AND A CORRESPONDENCE SURVEY FOR PERTINENT INFORMATION WAS CONDUCTED. FOUR PRINCIPAL OBJECTIVES FOR PROVIDING SAFER ROADSIDES WERE IDENTIFIED: (1) UNNECESSARY DRAINAGE STRUCTURES SHOULD BE LOCATED SO THAT THEY CREATE THE LEAST POSSIBLE HAZARD, (3) STRUCTURES WHICH CANNOT BE ELIMINATED OR REDESIGNED SHOULD BE DESIGNED TO INFLICT MINIMUM DAMAGE, AND (4) WHERE THE FIRST THREE OBJECTIVES CANNOT BE FEASIBLY ACCOMPLISHED, GUARDRAIL SHOULD BE INSTALLED. THE DESIGN AND LOCATION OF DRAINAGE STRUCTURES SHOULD RECEIVE AS MUCH ATTENTION FROM A SAFETY STANDPOINT AS OTHER ROADWAY FEATURES SUCH AS GEOMETRICS, LIGHTING, SIGNING, AND GUARDRAIL. THE SAFETY RESEARCH SHOWS THAT: (1) MEDIAN INLETS SHOULD BE FLUSH WITH THE GROUND SO AS TO PRESENT NO OBSTACLE TO A VEHICLE THAT IS OUT OF CONTROL, (2) END STRUCTURES FOR CROSS STREAMS OR CULVERTS SHOULD BE PLACED OUTSIDE THE DESIGNATED RECOVERY AREA WHEREVER POSSIBLE, (3) IF GRATES ARE NECESSARY TO COVER CULVERT INLETS, CARE MUST BE TAKEN TO DESIGN THE GRATES SO THAT THE INLET WILL NOT CLOG DURING THE FLOOD, (4) SET BACKS SHOULD BE MINIMAL WHERE CURB INLET SYSTEMS ARE USED, AND GRATES SHOULD BE DESIGNED FOR HYDRAULIC EFFICIENCY AND SAFE PASSAGE OF VEHICLES, (5) ROADSIDE CHANNELS SHOULD HAVE FLAT SIDE SLOPES, AND (6) HAZARDOUS CHANNELS OR ENERGY- DISSIPATING DEVICES SHOULD BE LOCATED OUTSIDE THE DESIGNATED RECOVERY AREA OR ADEQUATE GUARDRAIL PROTECTION SHOULD BE PROVIDED. THE KEY CRITERION FOR SAFETY APPEARS TO BE THAT POTENTIALLY DANGEROUS OPENINGS TO DRAINAGE STRUCTURES SHOULD BE SITUATED AWAY FROM THE ROADWAYS.

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    • 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. No 3, 38 Pp, 46 FIG, 3 TAB, 14 REF, 3 APP
  • Publication Date: 1969

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  • Media Type: Digital/other
  • Pagination: 38p
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    Open Access (libre)

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  • Accession Number: 00204256
  • Record Type: Publication
  • Files: TRIS, TRB, ATRI
  • Created Date: Mar 9 1970 12:00AM