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    <title>Transport Research International Documentation (TRID)</title>
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    <copyright>Copyright © 2026. National Academy of Sciences. All rights reserved.</copyright>
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    <managingEditor>tris-trb@nas.edu (Bill McLeod)</managingEditor>
    <webMaster>tris-trb@nas.edu (Bill McLeod)</webMaster>
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      <title>Transport Research International Documentation (TRID)</title>
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      <title>SECOND ANNUAL REPORT USE OF LARGE ROUGHNESS ELEMENTS FOR HYDRAULIC ENERGY DISSIPATION</title>
      <link>https://trid.trb.org/View/98867</link>
      <description><![CDATA[RESULTS OF EXPERIMENTS DEALING WITH THE UTILIZATION OF SIMPLE TRANSVERSE ROUGHNESS ELEMENTS FOR THE PURPOSE OF DISSIPATING ENERGY IN SMALL STRUCTURES SUCH AS HIGHWAY CULVERTS AND DRAINAGE DITCHES HAVE BEEN REPORTED PREVIOUSLY IN THE FIRST ANNUAL REPORT OF THIS PROJECT. AN EXTENSION OF THE ABOVE-MENTIONED EXPERIMENTS HAS BEEN CARRIED OUT AND THE RESULTS ARE REPORTED HEREIN AS A SUPPLEMENT TO THE FIRST ANNUAL REPORT. THE EXTENDED PORTION OF THE INVESTIGATION INCLUDES A STUDY OF THE EFFECT OF VARIOUS SHAPES OF TRANSVERSE BARS ON THE DEVELOPMENT OF FLOW REGIMES AND THE SELECTION OF THE TRIANGULAR-TOP ELEMENT AS AN OPTIMUM SHAPE; A STUDY OF THE MINIMUM LENGTH OF CHANNEL NECESSARY TO DEVELOP APPROXIMATELY UNIFORM TUMBLING FLOW THE ROUGHNESS ELEMENTS, AND AN ATTEMPT TO DEFINE MORE STRAIGHT-FORWARD DESIGN PROCEDURES THAN HAVE PREVIOUSLY BEEN DESCRIBED. QUALITATIVE RECOMMENDATIONS ARE PRESENTED FOR THE MINIMUM LENGTH OF CHANNEL. PREDICTION EQUATIONS ARE DEVELOPED FOR THE DRAG FORCE AND DRAG COEFFICIENT FOR THE TRIANGULAR-TOP ROUGHNESS ELEMENT AND THEY ARE COMPARED WITH THE CORRESPONDING EQUATIONS FOR THE SQUARE ROUGHNESS ELEMENT. COMPLETE DESIGN PROCEDURES ARE SET FORTH FOR THE USE OF SQUARE TRANSVERSE ROUGHNESS BARS INCLUDING AN EQUATION WHICH CAN BE USED FOR APPROXIMATE DESIGN FOR CASES WHICH FALL OUTSIDE THE EXPERIMENTAL RANGE OF APPLICABILITY. A SUMMARY OF EXPERIMENTAL DATA IS INCLUDED IN THE APPENDIX FOR RECTANGULAR CHANNELS ONLY. /AUTHOR/]]></description>
      <pubDate>Fri, 01 Apr 1994 00:00:00 GMT</pubDate>
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      <title>EAST LOS ANGELES INTERCHANGE OPERATION STUDY</title>
      <link>https://trid.trb.org/View/114747</link>
      <description><![CDATA[THE PERFORMANCE IS DESCRIBED OF PORTIONS OF THE EAST LOS ANGELES INTERCHANGE AS AFFECTED BY CHANGES IN STRIPING OF THE MERGING AREAS. THIS INTERCHANGE HAS AN AVERAGE DAILY TRAFFIC OF ABOUT 320,000 VEHICLES AND EXPERIENCES OPERATING DIFFICULTIES RESULTING IN LARGE DELAYS TO TRAFFIC. PAVEMENT MARKINGS AND RAISED BARS WERE USED TO CHANNELIZE THE MERGING AREAS INITIALLY. A BEFORE AND AFTER STUDY WAS CONDUCTED TO EVALUATE THE EFFECTS OF PROPOSED CHANGES IN ATTEMPTING TO EQUITABLY DISTRIBUTE DELAYS. AERIAL PHOTOGRAPHY, GROUND COUNTS AND FLOATING CAR RUNS WERE USED TO OBTAIN DATA TO EVALUATE THE OPERATION. COMPARISON OF THE CONDITIONS INDICATED THAT CHANNELIZATION CAN BE DETRIMENTAL, IF NOT PROPERLY DONE, STRIPING THAT IS LESS RESTRICTIVE CAN MORE EFFECTIVELY DISTRIBUTE DELAY THROUGHOUT THE TRAFFIC STREAMS, AND THE USE OF AERIAL PHOTOGRAPHY IS A PRACTICAL MEANS OF EVALUATING THE EFFECTS OF GEOMETRIC CHANGES ON TRAFFIC OPERATION.]]></description>
      <pubDate>Sun, 23 Jan 1994 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/114747</guid>
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      <title>LABORATORY AND FIELD STUDIES OF CHANNELING AND PUMPING</title>
      <link>https://trid.trb.org/View/182192</link>
      <description><![CDATA[Conditions that cause pumping and channeling in pavement systems were studied in the laboratory and the field. Laboratory pavement model tests indicated that dense-graded crushed-stone base courses would experience channeling and pumping under dynamic loading conditions.  An open-graded crushed-stone base did not pump, but subgrade intrusion caused permanent deformation of the pavement slab.  The University of Illinois test track was used to study six asphalt concrete pavement systems and four PCC pavement systems.  It was found that asphalt concrete pavements on both the nonstabilized and bituminous stabilized open-graded layers performed well under repeated wheel loads.  The pavement on a well-graded crushed-stone base displayed the poorest performance.  The PCC pavement slab on an open-graded base course did not pump, whereas that on a dense-graded base course displayed residual and dynamic pore-water pressures that led to pumping.  Field investigations show that pumping continues to be a problem in pavements.  However, it is indicated that the use of load transfer at pavement joints, nonerodible base materials, good drainage practices, and consideration of climatic conditions can lead to pavements that will perform well during the design life.  (Author)]]></description>
      <pubDate>Thu, 30 Dec 1982 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/182192</guid>
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    <item>
      <title>IMPROVING SUBDRAINAGE AND SHOULDERS OF EXISTING PAVEMENTS--FINAL REPORT</title>
      <link>https://trid.trb.org/View/176686</link>
      <description><![CDATA[Laboratory, test track and field results on channeling and pumping are presented.  The influence of water on pumping and erosion of fine material from beneath the pavement surface is clearly shown.  Methods for pavement drainage design in expansive soils and to resist the effects of frost action are presented.  It is shown that the depth and location of subdrain systems will influence the water flux.  Equipment and procedures for the maintenance and cleaning of subdrain pipes are discussed.  A hydraulic jet unit for cleaning pipe subdrains has been discussed in detail.  The influence of curb and gutter on pavement drainage has been briefly discussed.  Curb and gutter construction is normally used for roadway erosion control or in urban areas.  A drainage design philosophy is presented which explains the importance of predicting and controlling water contents in pavement drainage design.  The methods for controlling water contents in design consisted of protecting the pavement structural section, rendering pavement materials insensitive to water or evacuating the water from the pavement section.  (FHWA)]]></description>
      <pubDate>Thu, 30 Sep 1982 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/176686</guid>
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      <title>DYNAMIC ALLOCATION OF PARALLEL CONGESTED TRAFFIC CHANNELS</title>
      <link>https://trid.trb.org/View/39977</link>
      <description><![CDATA[Vehicular traffic flow in parallel channels of limited capacities is studied.  Optimal strategies for reducing the congestion during the rush period are derived from the standpoint of either individual or public interest.  It is demonstrated that when the two strategies derived from the above two standpoints are in conflict, certain incentives or compulsory regulations may be used in order to bring them together and minimize congestion.  A dynamic strategy for the optimal allocation of traffic into the channels is derived, which is adaptive to changes of the traffic demands and channel capacities.  /Author/]]></description>
      <pubDate>Tue, 30 Sep 1975 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/39977</guid>
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