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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>
    <docs>http://blogs.law.harvard.edu/tech/rss</docs>
    <managingEditor>tris-trb@nas.edu (Bill McLeod)</managingEditor>
    <webMaster>tris-trb@nas.edu (Bill McLeod)</webMaster>
    <image>
      <title>Transport Research International Documentation (TRID)</title>
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      <link>https://trid.trb.org/</link>
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    <item>
      <title>COMPARISON OF PORTABLE SPEED MEASUREMENT DEVICES</title>
      <link>https://trid.trb.org/View/741322</link>
      <description><![CDATA[The accuracy and precision of five common portable speed measurement systems were evaluated in a controlled field evaluation.  The following systems were evaluated: traffic classifier with pneumatic tubes, traffic classifier with piezoelectric sensors, tape switches, radar, and lidar (i.e., police laser).  A test vehicle with a calibrated Nitestar distance-measuring instrument (DMI) made 100 passes through the test site at two speed levels (50 passes at 55 mph, 50 passes at 35 mph), and speed was recorded by each device for each pass. DMI speed was deemed the true speed for each pass, and deviations from the DMI speed for a given device were considered errors.  Paired t-tests were performed on the speed data measured by each device versus the DMI.  The following conclusions were drawn: (a) All devices performed equally well for the 35-mph trials.  (b) Lidar and radar were the most accurate and precise devices for the 55-mph trials.  (c) For all devices, any errors that occurred for a single speed measurement were relatively small (less than +/- 1.5 mph).  (d) With the exception of radar, all devices were slightly less accurate and less precise at higher speeds.  (e) There was little difference in performance between on-pavement devices (i.e., tubes, piezoelectric sensors, and tape switches).  (f) Inaccuracies observed in on-pavement equipment likely were caused by slight measurement errors during placement of the sensors or movement of the sensors resulting from repeated tire hits.  Because all devices were relatively accurate, the researchers recommended that portable speed measurement equipment be selected to suit the characteristics of a given data collection situation.]]></description>
      <pubDate>Wed, 29 Sep 2004 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/741322</guid>
    </item>
    <item>
      <title>CLASSIFYING SAND BY ELUTRIATION</title>
      <link>https://trid.trb.org/View/107021</link>
      <description><![CDATA[THE PRINCIPLE THAT THE VELOCITY AT WHICH A SOLID PARTICLE SETTLES WHEN PLACED IN WATER DEPENDS ON THE SIZE, AND WEIGHT OF THAT PARTICLE HAS BEEN USED IN VARIOUS WAYS FOR CLASSIFYING PARTICULATE MATERIALS. A RECENTLY INTRODUCED LARGE-SCALE SAND CLASSIFIER ADOPTS THIS PRINCIPLE WHICH WAS ORIGINALLY APPLIED BY A. LOVEGREEN OF THE HYDRAULICS RESEARCH STATION TO THE DESIGN OF AN ELUTRIATOR. THIS PAPER DESCRIBES INSTALLATIONS IN GRAVEL WORKINGS AT WHISBY NEAR LINCOLN AND BRANDON NEAR COVENTRY.]]></description>
      <pubDate>Tue, 06 Dec 1994 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/107021</guid>
    </item>
    <item>
      <title>THE EFFECT OF THE CLASSIFICATION OF SAND ON THE STRENGTH OF CONCRETE</title>
      <link>https://trid.trb.org/View/98611</link>
      <description><![CDATA[AS THE TECHNOLOGY OF CONCRETE DEVELOPED, GREAT IMPORTANCE BEGAN TO BE ATTRIBUTED TO THE ROLE PLAYED BY THE SURFACE OF FINE AND FINEST GRAINS IN A CONCRETE MASS. METHODS WERE SOUGHT WHICH WOULD ELIMINATE UNNECESSARY FRACTIONS FROM SAND. USING A WATER CLASSIFIER WAS ONE OF THE METHODS. NOT ONLY WAS SAND EASILY SEPARTED IN THIS APPARATUS INTO TWO OR MORE FRACTIONS, BUT IT WAS COMPLETELY FREED OF IMPURITIES AND THE FINEST FRACTIONS. A DESCRIPTION IS GIVEN OF THE OPERATION OF THE CLASSIFIER AND OF THE WAY AN EXAMINATION IS MADE. THREE FRACTIONS OBTAINED FROM THE CLASSIFIER WERE USED' ELUTRIATED GRAVEL /3-20 MM/, ELUTRIATED FINE SAND /0.8-3 MM/ AND ELUTRIATED FINE SAND /0.1-0.8/. GRADES OF CEMENT 350 AND 400 WERE USED FOR THE EXAMINATION. THE WATER- CEMENT RATIO VARIED FROM 0.57 TO 0.32. IT WAS FOUND THAT LARGE DIFFERENCES IN STRENGTH WERE OBTAINED BY USING THE PROPER SAND POINT WHEN A CHANGE WAS MADE IN THE PROPORTIONS OF FINE TO COARSE SAND. THE BEST RESULTS WERE OBTAINED AT A 33 PERCENT SAND POINT WHEN THERE WAS AN AMOUNT OF 60 PERCENT OF FINES IN THE TOTAL AMOUNT OF SAND. THE FOLLOWING COMPRESSION STRENGTH WAS OBTAINED AFTER 28 DAYS FOR GRADE OF CEMENT 400, DOSED IN AMOUNTS OF 500 KG PER CU M' GRAVEL AND UNWASHED SAND-271 KG PER SQ CM, GRAVEL AND ELUTRIATED SAND- 612 KG PER SQ CM. /CR/]]></description>
      <pubDate>Tue, 30 Aug 1994 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/98611</guid>
    </item>
    <item>
      <title>ROUGHNESS INDEX STANDARDS FOR SASKATCHEWAN PAVEMENTS</title>
      <link>https://trid.trb.org/View/100500</link>
      <description><![CDATA[A BRITISH MULTI-WHEELED PROFILOMETER WAS USED TO ESTABLISH TENTATIVE ROUGHNESS INDEX STANDARDS FOR ASPHALT PAVEMENTS IN SASKATCHEWAN. INDICES WERE BASED ON PROFILOMETER INTEGRATOR PLOTS, PROFILES, AND CLASSIFIER READINGS FROM APPROXIMATELY 150 MILES OF SELECTED STANDARDS PAVEMENT EFFECTS AND COMPARED WITH SUBJECTIVE PERFORMANCE RATINGS BEFORE INDEX STANDARDS WERE SET. ANALYSIS OF DATA INDICATED THAT PAVEMENTS RATED GOOD BY SASKATCHEWAN MATERIALS PERSONNEL HAD CORRECTED ROUGHNESS INDICES OF 38 INCHES PER MILE OR LESS. THE STANDARDS ARE TENTATIVE, PENDING ANALYSIS OF 1966 DATA. /CGRA/]]></description>
      <pubDate>Fri, 29 Jul 1994 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/100500</guid>
    </item>
    <item>
      <title>THE DISTRIBUTION RING SEPARATOR</title>
      <link>https://trid.trb.org/View/101862</link>
      <description><![CDATA[THE DISTRIBUTION RING SEPARATOR IS A NEW CIRCULATING AIR SEPARATOR WHICH, CONTRARY TO THE CONVENTIONAL SEPARATORS, SEPARATES THE FINE MEAL IN THE CENTRAL INNER CHAMBER. THE FEED MATERILA IS DISTRIBUTED BY MEANS OF THE EXTERNAL DISTRIBUTION RING. THE CLASSIFYING WHEEL IS DRIVEN SEPARATELY FROM THE CIRCULATING AIR FAN, WHICH ONLY HAS TO SUPPLY CLEAN AIR. POWER CONSUMPTION AND WEAR ARE LESS FOR THIS SEPARATOR THAN FOR THE CONVENTIONAL TYPES. SPECIAL SHORT VERSIONS HAVE BEEN DEVELOPED FOR LIMITED SPACE CONDITIONS. MANY DETAILS SHOW THE SUPERIORITY OF THE NEW CONSTRUCTIONS. OUTPUT FIGURES UP TO 200 T/HR FOR CEMENT GRADES Z 275, 375 AND 475 ARE GRAPHICALLY REPRESENTED FOR THE SIZE RANGE ACCORDING TO SERIES R 20. /AUTHOR/]]></description>
      <pubDate>Thu, 05 May 1994 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/101862</guid>
    </item>
    <item>
      <title>AUTOMATIC MEASUREMENT OF CEMENT FINENESS</title>
      <link>https://trid.trb.org/View/101872</link>
      <description><![CDATA[THE AUTOMATIC PREMEABILIMETER DEVELOPED BY THE HOLDERBANK TECHNICAL CENTRE IS DESCRIBED IN DETAIL. WITH THIS APPARATUS IT IS POSSIBLE TO CARRY OUT QUASI-CONTINUOUS MEASUREMENT OF THE SPECIFIC SURFACE BY BLAINE'S METHOD ON CEMENT SPECIMENS WEIGHING 250 G EACH. A MEASUREMENT IS OBTAINED EVERY 4 MINUTES. THE APPARATUS CAN SUITABLY BE USED FOR CONTROLLING A CLASSIFIER. /AUTHOR/]]></description>
      <pubDate>Sun, 23 Jan 1994 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/101872</guid>
    </item>
    <item>
      <title>VEHICLE DETECTION-PHASE III: PASSIVE BUS DETECTOR/INTERSECTION PRIORITY SYSTEM OPTION II: MFG. DRAWINGS AND PROTOTYPE DEVELOPMENT. CLASSIFIER HANDBOOK</title>
      <link>https://trid.trb.org/View/168781</link>
      <description><![CDATA[This handbook is directed towards the engineers who will be adapting the Passive Bus Detector/Classifier to new vehicle identification problems.  The handbook begins with a discussion of the passive bus sensor characteristics that are important for vehicle identification.  Next, the basic ideas of Pattern Recognition are introduced and discussed from a geometric and trial-and-error point of view.  The basic theory of optimal classifier design is presented and compared with the preceding geometric discussion by using the idea data set complexity.  These ideas and the operation of the Cascaded Threshold Classifier program are illustrated with two detailed numerical examples.  The final chapter of the handbook gives a step-by-step description of the design of the original bus classifier, showing the reasoning and method used in developing the classifier equations.  This handbook is written with the idea that optimal methods work well for optimal problems, but practical problems need practical solutions.  The Cascaded Threshold Classifier program attempts to meet this practical need.  It contains a variety of data manipulation subroutines, including optimal classifier solutions, along with a control structure tht allows the user to apply them interactively and thus discover the characteristics of the data and develop the classifier in small steps.  A complete flowchart of the program and a fully annotated Fortran listing are included. (FHWA)]]></description>
      <pubDate>Tue, 22 Dec 1981 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/168781</guid>
    </item>
    <item>
      <title>VEHICLE DETECTION, PHASE III: PASSIVE BUS DETECTOR/INTERSECTION PRIORITY SYSTEM DEVELOPMENT. OPTION II: MANUFACTURING DRAWINGS AND PROTOTYPE DEVELOPMENT</title>
      <link>https://trid.trb.org/View/89272</link>
      <description><![CDATA[A production prototype 16-channel Passive Bus Detector (PBD) was developed, based on the engineering model Passive Bus Detector/Intersection Priority System. The PBD is functionally the same as the engineering model except that the traffic controller function was not carried along into the production prototype mode. The PBD was repackaged to facilitate production and evaluated in an intersection with a typical traffic controller. Operation in the intersection for a 2-month period was successful.]]></description>
      <pubDate>Sat, 17 Oct 1981 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/89272</guid>
    </item>
    <item>
      <title>RECOVERING METAL FROM NONMAGNETIC AUTO-SHREDDER REJECT</title>
      <link>https://trid.trb.org/View/29722</link>
      <description><![CDATA[Various methods of metal recovery from nonmagnetic auto-shredder reject scrap including air classification, water elutriation, screening, handsorting, and heavy media separation were investigated. Projected metal recoveries in an integrated process are 39 percent copper and copper alloys, 53 percent aluminum, 96 percent iron, and 98 percent zinc die-cast. An economic evaluation of the conceptual process indicated profitable operation of a facility designed to separate daily the reject scrap from 200 shredded automobiles. Total investment in this plant would be $321,000, and the discounted rate of return before taxes would be 53 percent.]]></description>
      <pubDate>Fri, 03 Dec 1976 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/29722</guid>
    </item>
    <item>
      <title>RECOVERING POLYURETHANE FOAM AND OTHER PLASTICS FROM AUTO-SHREDDER REJECT</title>
      <link>https://trid.trb.org/View/42466</link>
      <description><![CDATA[A cooperative study was made by the Federal Bureau of Mines and the Ford Motor Co. to investigate the recovery of polyurethane foam and other assorted plastics from the nonmagnetic rejects from automobile shredders. The material used in the study was produced by the shredding of two 1972 Montegos provided by Ford. The proposed flowsheet, as developed by the Bureau, consisted of a combination of screening, water classification, and gravity separation. All of the foam and between 52 and 80 pct of the assorted plastics were recovered. The reclaimed foam concentrates which contained 63 pct foam were hydrolyzed in laboratory tests to produce a potentially reusable liquid mixture of polyether glycol monomers and toluene diamine.]]></description>
      <pubDate>Tue, 13 Jul 1976 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/42466</guid>
    </item>
    <item>
      <title>SAND SEGREGATION IN HYDRAULIC CLASSIFERS</title>
      <link>https://trid.trb.org/View/140506</link>
      <description><![CDATA[The construction and principle of operation is described of hydrocyclones and of hydroclassifiers.  The former consists of two principal parts, viz, a cylindrical head from which runs out centrally an overflow nozzle, to which is attached (tangentially) an intake nozzle; and a conical unit at the end of which is a discharging nozzle.  The hydroclassifiers are of 2 basic types: the type devoid of a rising jet of pure water, and those types provided with such a jet of water.  Those of the latter type are more complex equipment. The use of hydrocyclones as classifiers was investigated. The electrical energy consumption of classifiers and the costs of production of hydroclassified sand are discussed, and an empirical equation for the calculation of the energy requirement for classifying 1 cu m of sand is presented.]]></description>
      <pubDate>Tue, 11 Feb 1975 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/140506</guid>
    </item>
    <item>
      <title>UTILIZATION OF INDUSTRIAL WASTE IN HIGHWAY EMBANKMENT CONSTRUCTION</title>
      <link>https://trid.trb.org/View/134827</link>
      <description><![CDATA[In an effort to demonstrate the practicality of utilizing exclusively classified mill tailings for highway enbankment construction, a proposal was made that called for constructing a graded and drained roadway, which included major separation structures at 3 locations and a section of Salt Lake County storm drain.  Total waste accumulation from a mulling operation amounts to 700 million cubic yards of mill tailings which have been deposited in a spoils pond covering 5200 acres, 85 feet in height and which is rising at the rate of 3 to 4 feet per year.  The mill run tailings were classified, dewatered and made available at the rate and quantity necessary to satisfy the needs of the project, and at a cost competitive with material from other available sources.  Details are given of the classifying, and construction features are outlined.  This project has demonstrated that the tailings are a quality embankment material, and that they can produced and delivered for use economically.]]></description>
      <pubDate>Wed, 06 Nov 1974 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/134827</guid>
    </item>
    <item>
      <title>SOIL PARTICLE SIZE DISTRIBUTION BY A CENTRIFUGE METHOD IN COMPARISION WITH SEDIMENTATION PROCESSES, WITH DISCUSSIONS AND CLOSURE</title>
      <link>https://trid.trb.org/View/120212</link>
      <description><![CDATA[A CENTRIFUGAL SEDIMENTATION METHOD FOR THE ISOLATION OF PARTICLES OF SOIL IN THE MICRON AND SUB-MICRON RANGE GAVE RESULTS COMPATIBLE WITH THE CURVES OBTAINED BY THE STANDARD HYDROMETER PROCEDURE. THE METHOD REDUCES TEST TIME FROM 72 HOURS TO ONE-HALF HOUR. IT HAS THE ADDITIONAL ADVANTAGE OF PROVIDING MATERIAL SUITABLE FOR SPECIALIZED RESEARCH IN THE ASSESSMENT OF GRAVEL FOR ROAD WORKS.]]></description>
      <pubDate>Wed, 28 Jun 1972 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/120212</guid>
    </item>
    <item>
      <title>CENTRIFUGAL MODEL TESTING OF SOILS</title>
      <link>https://trid.trb.org/View/120192</link>
      <description><![CDATA[A CENTRIFUGAL MODEL TECHNIQUE, FOR PREDICTING DIRECTLY THE BEHAVIOR OF FOUNDATIONS AND EARTHWORKS, IS EVALUATED. A PARTICULARLY VALUABLE ADVANTAGE OF THE METHOD IS ITS ABILITY TO SHORTEN THE TIME REQUIRED FOR THE DEVELOPMENT AND DISSIPATION OF PORE PRESSURES PRODUCED IN THE PROTOTYPE. DEFLECTIONS IN THE MODEL SURFACE ARE MEASURED BY PHOTOGRAMMETRY, AND A VIEW OF THE MODEL SURFACE IS CONTINUOUSLY DISPLAYED ON A TELEVISION MONITOR. PORE PRESSURES IN THE MODEL CAN BE MEASURED BY TRANSDUCERS. EXAMPLES OF SOLUTIONS TO PRACTICAL PROBLEMS ARE PRESENTED. THE RESEARCH HAS CONFIRMED THE POTENTIAL OF THE CENTRIFUGAL TESTING OF A SOIL MODEL AS A PRACTICAL DESIGN TOOL. /RRL/]]></description>
      <pubDate>Tue, 09 May 1972 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/120192</guid>
    </item>
    <item>
      <title>MODERN PLANTS MAKE AGG FROM WASTE</title>
      <link>https://trid.trb.org/View/107511</link>
      <description><![CDATA[AS EXISTING PITS RUN LOW AND ENVIRONMENTAL-PROTECTION PRESSURES INCREASE, PRODUCERS ARE TURNING TO WASTES, INFERIOR DEPOSITS, AND BOTTOM-OF-THE-PIT MATERIAL. LARGER, AUTOMATED, AND MORE POWERFUL STATIONARY AND PORTABLE EQUIPMENT IS BEING MANUFACTURED TO HANDLE THIS MATERIAL, SUCH AS PEA GRAVEL, CLAYS AND SHALES, AND SURPLUS CRUSHER FINES. AMONG THE EQUIPMENT ARE CONE AND CAGE CRUSHERS, WASHERS, SCRUBBERS, SCREW CLASSIFIERS, DEWATERING TANKS, AND MIXING SYSTEMS. TYPICAL EQUIPMENT IS DESCRIBED, AND A PLANT WITH MULTIPRODUCT OUTPUT CAPABILITY IS DIAGRAMMED. A TABLE LISTS THE CHARACTERISTICS OF 16 SAND AND STONE MACHINES WHOSE SPECIFICATIONS AND FURTHER INFORMATION CAN BE ORDERED FROM THIS JOURNAL.]]></description>
      <pubDate>Sun, 03 Oct 1971 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/107511</guid>
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