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    <title>Transport Research International Documentation (TRID)</title>
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    <atom:link href="https://trid.trb.org/Record/RSS?s=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" rel="self" type="application/rss+xml" />
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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>
      <url>https://trid.trb.org/Images/PageHeader-wTitle.jpg</url>
      <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>FIELD EVALUATION OF FHWA VEHICLE CLASSIFICATION CATEGORIES--MDOT. EXECUTIVE SUMMARY</title>
      <link>https://trid.trb.org/View/214711</link>
      <description><![CDATA[Four systems are available, programmable to classify vehicles to the FHWA scheme.  In a study conducted by the Main Facility (Lyles, Wyman; July 31, 1982; Evaluation of Vehicle Classification Equipment) a scheme "E" was selected from five candidate schemes and recommended to the FHWA for adoption as a standard.  In order to correct logic errors in that scheme and to add categories for mototcycles and buses the classification scheme "E" logic has been changed and a new scheme called "F" has been evolved.  This scheme "F" has been evaluated and appears workable as a classification scheme at about 95% classification accuracy.  The I.R.D. unit is a permanent all weather system.  The Golden-River unit is a semi-permanent, clear road system only.  The Streeter-Amet unit and the G.K. Inst.  Units are clear road systems using pneumatic tubes only.  The fifth system tested, a Sarasota unit classifies by road loops to 7 length categories only.  Sarasota expects to have the same electronic package operating from road tubes with scheme E or F programs available after January, 1985.  All systems operated satisfactorily during the three month test period within the limitations listed under the Detailed Evaluation. (Author) Evaluation.  (Author)]]></description>
      <pubDate>Wed, 25 Aug 2004 01:39:58 GMT</pubDate>
      <guid>https://trid.trb.org/View/214711</guid>
    </item>
    <item>
      <title>TECHNOLOGIES FOR TRUCK CLASSIFICATION AND METHODOLOGIES FOR ESTIMATING TRUCK VEHICLE MILES TRAVELED</title>
      <link>https://trid.trb.org/View/683943</link>
      <description><![CDATA[Results are presented of a national survey of all state departments of transportation (DOTs), including Puerto Rico, about technologies used for truck classification and methodologies used for estimating truck vehicle miles traveled (VMT).  More than two-thirds of state DOTs returned the survey. Procedures were found to classify trucks, to adjust truck data from short-term counts, and to calculate truck VMT.  To classify trucks, most state DOTs followed the Federal Highway Administration's 13 categories.  The products from two manufacturers, Peek Traffic and Diamond Traffic Products, with a variety of sensors, dominated the classification devices used by state DOTs.  The sensor used most for short-term classification counts was the pneumatic tube.  Duration and number of truck-classification counts (machine or manual) varied by state DOT.  With machine classifiers, state DOTs collected short-term and continuous truck data for a variety of state highway coverage.  Truck data were collected by using machine classifiers unless certain conditions, such as congested highways, demanded manual collection.  To adjust truck data from short-term classification counts, most state DOTs developed their adjustment factors from continuous volume counts (not truck counts) and used them to adjust truck volumes.  Some state DOTs used different adjustment factors for trucks and cars.  For all state DOTs, the general practice of truck VMT estimation was based on traffic counts.  When truck data were available, state DOTs directly calculated truck VMT by multiplying truck average daily traffic and the length of a roadway section; when the data were not available, truck VMT was indirectly calculated as a fraction (percentage) of total VMT.  For the state highway systems, state DOTs generally relied on the first (direct) method, since the resources were normally available and the standards for conducting traffic counts were also available. However, some states lacked the necessary resources to adequately sample average daily traffic on the local road systems.  As a result, many state DOTs used the indirect method to calculate truck VMT.]]></description>
      <pubDate>Tue, 30 Dec 2003 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/683943</guid>
    </item>
    <item>
      <title>ACCURACY AND VISIBILITY OF SPEED MEASUREMENT DEVICES</title>
      <link>https://trid.trb.org/View/481620</link>
      <description><![CDATA[The research in this paper focuses on evaluating six commonly used speed measurement devices based on accuracy and driver response. These were: Pneumatic Tubes; Magnetic Sensor; Human Observer; Radar; Tapeswitches; and Lidar. The speeds measured with these devices were compared with speeds computed using the Lateral Acceleration Sensor System (LASS), a speed measurement device developed by the Federal Highway Administration (FHWA). Each device was evaluated over speeds ranging from 10 to 55 mph. In addition, each device was set up on a low-speed, urban street and tested for visibility to drivers. A device was said to be "visible" if the vehicle displayed its brakelights. The results of this research will help traffic engineers make informed decisions regarding speed research in suburban neighborhoods.]]></description>
      <pubDate>Wed, 12 Mar 1997 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/481620</guid>
    </item>
    <item>
      <title>MATHEMATICAL CORRECTION OF AXLE UNDERCOUNTING IN PNEUMATIC TUBES TRAFFIC SURVEYS</title>
      <link>https://trid.trb.org/View/307134</link>
      <description><![CDATA[This is a report on mathematical correction of undercounting of axles by pneumatic tube traffic counters on multilane roads.  The strategem is based on estimating the shadow of counter inactivity presented to other lanes when an axle goes over a pneumatic tube in a given lane.  The assumptions that justify the analysis are listed. Forumlas are presented that have have been checked by simulation.  In the case of pulsed traffic,  special computations are necessary to account for the traffic volume incrementally.]]></description>
      <pubDate>Sat, 31 Mar 1990 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/307134</guid>
    </item>
    <item>
      <title>AXLE SENSORS MEASURE UP</title>
      <link>https://trid.trb.org/View/300540</link>
      <description><![CDATA[A sensor consists of a sensing element encapsulated in an elastomeric cover for added protection.  The sensing element and shape or form of the cover are determined by the application and the type of installation required.  This article describes the types of sensing elements (pneumatic tubes, tribo-electric cables, piezo-electric, treadles, piezo-resistive, and capacitive) and the encapsulation forms available.  The combination of element and encapsulation form are then compared in table form.]]></description>
      <pubDate>Thu, 31 Aug 1989 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/300540</guid>
    </item>
    <item>
      <title>AUTOMATIC VEHICLE CLASSIFICATION TECHNIQUES: LANE, SPEED AND BASIC TYPE CLASSIFICATION</title>
      <link>https://trid.trb.org/View/196019</link>
      <description><![CDATA[This paper, the first of a series describing the current position in microprocessor-based techniques, discusses relatively simple commercially available techniques. Examples are given of the results of accuracy studies carried out on speed and simple type classification equipment.  Microprocessor systems are a sealed counting unit without moving parts but with programming ability to permit some analysis and data compression before storing for further analysis on a mainframe computer.  The processor can also be programmed to collect the form of data best suited to the particular needs of the individual user.  Almost all counting at present is carried out using pneumatic tubes or inductive loops; the author describes their methods of installation, illustrating configurations commonly used for lane classification and speed and type classification. Results suggested that some small systematic discrepancies can occur which are reduced by individual site calibration. Errors in classification only occurred with a small proportion of the vehicles.  (TRRL)]]></description>
      <pubDate>Fri, 30 Dec 1983 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/196019</guid>
    </item>
    <item>
      <title>PNEUMATIC CONVEYING TECHNIQUES IN THE CONSTRUCTION INDUSTRY</title>
      <link>https://trid.trb.org/View/179634</link>
      <description><![CDATA[The author reviews developments in the field of pneumatic transport of solids and introduces the subject of semi-bulk handling.  Aspects of handling dry bulk solids have been investigated at the University of Witwatersrand.  Although there are various modes of pneumatic conveying, the paper concentrates on dense phase conveying which involves the transport of a product as a dense plug.  Such systems facilitate a high discharge rate from relatively small tubes with low velocity within the system.  Details of modes of operation and equipment for air/solid separation are described.  Examples are given of the implementation of pneumatic conveying on construction sites in the handling of dry concrete and placing of concrete.  (TRRL)]]></description>
      <pubDate>Fri, 28 May 1982 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/179634</guid>
    </item>
    <item>
      <title>EXPERIMENTAL VERIFICATION OF A PNEUMATIC TRANPSORT SYSTEM FOR THE RAPID EXCAVATION OF TUNNELS PART II--TEST PROGRAM</title>
      <link>https://trid.trb.org/View/84406</link>
      <description><![CDATA[This study is the final phase of a muck pipeline program begun in 1973.  The objective of the study was to evaluate a pneumatic pipeline system for muck haulage from a tunnel excavated by a tunnel boring machine.  The system was comprised of a muck preparation unit, solids feeder and air blower, telescoping pipes and 500 feet of 10-inch diameter pipe.  The system transported up to 100tph of simulated tunnel muck with maximum sizes ranging from 1/2 inch to more than 3 inches.  The system components were tested for reliability and flexibility, wear and maintenance requirements, capacity, noise and dust levels, effect of moisture content, extensibility, and power requirements. The system was found to be low in capital cost, easy to operate, and readily extensible.  The pneumatic pipeline was power-intensive and susceptible to elbow wear.  For the pneumatic transport of coarse muck, moisture content was more important than particle size.  Noise levels were high at the blower and muck preparation unit but could be reduced in actual practice.  The system was found to be reliable except for the elbow wear.  Related reports have been issued, namely: "Pneumatic-Hydraulic Material Transport System for Rapid Excavation of Tunnels," DOT-TST-75-17; "Experimental Verification of a Pneumatic Transport System for the Rapid Excavation of Tunnels, Part I: Installation of Test Facility," DOT-TST-76-63; and "Transportation of Tunnel Muck by Pipeline," UMTA-MA-06-0025-78-4.  Loan copies are available from the Transportation Systems Center, Kendall Square, Cambridge, Massachusetts 02142.  /UMTA/]]></description>
      <pubDate>Tue, 31 Jul 1979 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/84406</guid>
    </item>
    <item>
      <title>LIFE OF AUTOMATIC PUNCHED TAPE TRAFFIC COUNTER AND DETECTOR INSTALLATIONS</title>
      <link>https://trid.trb.org/View/80716</link>
      <description><![CDATA[A study was made to show how long automatic traffic counters, detector tubes or loop detector installations operated at permanent counting stations before any replacement was needed.  The results show that although traffic counters have their own nominally weatherproof housings, the provision of additional shelter at permanent installations extended the life of the counter by well over 50 percent in terms of days at site and by about 50 percent in terms of vehicles counted.  The replacement of pneumatic tubes by inductive loop installation produced a tenfold extension of detector life before any sort of failure. /Author/]]></description>
      <pubDate>Sat, 03 Feb 1979 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/80716</guid>
    </item>
    <item>
      <title>CALCULATION OF THE ENGINE THRUST REQUIRED TO MOVE A CAR IN A TUBE</title>
      <link>https://trid.trb.org/View/60532</link>
      <description><![CDATA[The motion of a car in an infinite tube under the effect of a turbojet engine is considered.  A solution is obtained for the problem of unsteady gas flow arising when a car moves along at a constant velocity.  The value of drag and the thrust force necessary for the motion are determined.  A formula is found to determine the asymptotic value of the force.]]></description>
      <pubDate>Fri, 13 Jan 1978 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/60532</guid>
    </item>
    <item>
      <title>PNEUMATIC TUBE TRANSPORTATION</title>
      <link>https://trid.trb.org/View/35899</link>
      <description><![CDATA[The results of basic research on the pneumatic tube system are used to project significant operating characteristics of a prototype pneumatic tube transportation system.  The projections are based on an experimentally verified, numerically computed analysis and laws of similitude. Background and other pneumatic tube studies are noted. Vehicle speed variations on the guideway due to air friction and compressibility during a transit are shown for the prototype double-tube system to be acceptable at moderate speeds.  Guideway power is shown to be strongly affected by vehicle average speed, to be essentially directly proportional to guideway discharge pressure, and to be little influenced by the vehicle weight.  The technical feasibility of the investigated features of the concept is supported.]]></description>
      <pubDate>Wed, 10 Mar 1976 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/35899</guid>
    </item>
    <item>
      <title>CONTROL CONCEPTS FOR PNEUMATIC-TUBE VEHICLES</title>
      <link>https://trid.trb.org/View/39158</link>
      <description><![CDATA[The pneumatic-tube transport system, its operation, and its conceptual development as a high-speed-ground-transportation alternative are discussed briefly. Schemata for control of passive and nonpassive tube vehicles are proposed. System simulations employing a Fanno-flow model and each of the control schemata are outlined. Results contrasting controlled and uncontrolled system operations are presented as plots of the vehicle's velocity and acceleration versus the vehicle's position in the tube. Results evidence the infeasability of existing, passive vehicle concepts. /Author/]]></description>
      <pubDate>Tue, 15 Jul 1975 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/39158</guid>
    </item>
    <item>
      <title>IMPROVEMENT OF THE POLISHED STONE VALUE OF SLAG ROADSTONE BY HEAT TREATMENT</title>
      <link>https://trid.trb.org/View/109709</link>
      <description><![CDATA[THE AUTHORS DESCRIBE STUDIES CARRIED OUT TO IDENTIFY THE MINERALOGICAL CRYSTALLOGRAPHIC AND PHYSICAL PROPERTIES WHICH INFLUENCE THE PSV OF BLAST FURNACE SLAG ROADSTONE WITH A VIEW TO IMPROVING THE PSV OF SLAG WITHOUT CAUSING DETERIORATION IN WEAR RESISTANCE.  IT WAS FOUND THAT THE COMPOUNDS PRESENT IN THE SLAG HAVE DIFFERING PSV, AND THAT PSV OF SLAG DEPENDS PREDOMINANTLY ON CRYSTALLINE TEXTURE AND POROSITY. IT WAS ESTABLISHED THAT BOTH INCREASED CRYSTAL SIZE AND INCREASED POROSITY IMPROVE THE PSV OF BLAST FURNACE SLAG BUT LARGE POROSITY DEGRADED THE WEARING PROPERTIES OF THE AGGREGATE AND WOULD HAVE RESULTED IN A SHORTENED USEFUL LIFE AS A ROADSTONE. INCREASING THE SIZE OF THE CRYSTALS IN BLAST FURNACE SLAG PROVED TO BE A PRACTICABLE WAY OF IMPROVING ITS PSV. THIS DESIRED CHANGE IN CRYSTAL DIMENSIONS WAS ACHIEVED BY PLANNED HEAT TREATMENTS.  THE HEAT TREATMENT PRODUCED SOME CHANGES IN THE CHEMICAL PHASE ASSEMBLAGE OF THE SLAGS AND THESE HAD A MINOR EFFECT ON PSV.  WHERE THESE CHANGES WERE ACCOMPANIED BY AN INCREASE IN THE RANGE OF MICROHARDNESS THE PSV WAS ALSO INCREASED. THE BEST IMPROVEMENT IN THE PSV OF SLAGS WAS OF THE ORDER OF 10 UNITS. THE INFLUENCE OF CRYSTAL SIZE WAS FURTHER DEMONSTRATED BY ACHIEVING A 10 UNIT DECREASE IN THE PSV OF SLAGS BY MEANS OF A HEAT TREATMENT WHICH LED TO CRYSTALS MUCH SMALLER THAN THOSE PRESENT INITIALLY. A QUANTITY OF ONE SLAG HAS BEEN HEAT TREATED TO IMPROVE ITS PSV AND ROAD TESTED FOR SKID RESISTANCE WITH SATISFACTORY RESULTS.]]></description>
      <pubDate>Fri, 24 May 1974 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/109709</guid>
    </item>
    <item>
      <title>GOODS TRANSPORT IN ETAREA</title>
      <link>https://trid.trb.org/View/92506</link>
      <description><![CDATA[A DESCRIPTION IS PRESENTED OF PLANS FOR ETAREA, A SATELLITE TOWN OF PRAGUE, THEY INCORPORATE A UNIQUE APPROACH TO THE RELATED PROBLEMS OF STORAGE AND DISTRIBUTION OF GOODS WITHIN URBAN AREAS. ALL JINCOMING GOODS WILL BE DELIVERED BY ROAD OR RAIL, AND POSSIBLY IN THE FUTURE BY WATER, TO A CENTRAL STORAGE COMPLEX. GOODS FOR THE RETAIL TRADE ARE DISTRIBUTED FROM THIS CENTRAL STORE BY AUTOMATED TRAINS PULLED BY BATTERY-POWERED TRUCKS, EACH TRAIN HAVING A CAPACITY OF 8.75 TONS. THE TRAINS, WHICH RUN IN A NETWORK OF UNDERGROUND TUNNELS, 2 X 2.5 METERS IN CROSS SECTION, ARE GUIDED BY AN OPTICAL SENSING SYSTEM. THE UNDERGROUND NETWORK COMPRISES 3 MAIN ROUTES WITH BRANCHES SERVING THE INDIVIDUAL CENTERS. SECONDARY STORAGE FACILITIES ARE PLANNED FOR EACH OF THE 14 RETAIL CENTERS WHERE UNIT LOADS RECEIVED FROM THE MAIN STORAGE CENTER ARE SUBDIVIDED FOR RETAIL SALE. ONE OF THE PROPOSED METHODS OF RETAIL DISTRIBUTION PROVIDES FOR THE FULLY AUTOMATED DELIVERY OF GOODS FROM THE RETAIL CENTERS DIRECT TO THE CONSUMER'S HOUSEHOLD. THIS IS ACCOMPLISHED BY MEANS OF A PNEUMATIC TUBE SYSTEM. ORDERS WILL BE PLACED BY DIALING THE CODE NUMBER ASSIGNED TO THE REQUIRED ITEM, GIVEN IN, A CATALOGUE OF AVAILABLE GOODS. PROVIDED THAT THE CUSTOMERS ACCOUNT IS IN CREDIT THE ORDER WILL BE ACCEPTED AND THE GOODS AUTOMATICALLY DISPATCHED FROM THE LOCAL CENER; DELIVERY IS ESTIMATED TO TAKE BETWEEN 2.5 AND 11.5 MINUTES DEPENDING ON THE DISTANCE OF THE CUSTOMER'S HOUSE FROM THE CENER. THE SAME SYSTEM IS UTILIZED FOR THE DELIVERY OF REGULAR ORDERS FOR SUCH ITEMS AS NEWSPAPERS AND MAGAZINES AS WELL AS FOR MAIL AND FOR THE REMOVAL OF HOUSEHOLD REFUSE. IN ADDITION TO THE AUTOMATED SYSTEM EACH RETAIL CENTER WILL HAVE OVER-THE-COUNTER, SELF-SERVICE AND SLOT MACHINE FACILITIES FOR THE SALE OF GOODS. ALL PROPOSALS FOR GOODS STORAGE AND DISTRIBUTION PLANNED FOR ETAREA ARE BASED ON EXISTING TECHNOLOGIES.]]></description>
      <pubDate>Wed, 15 May 1974 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/92506</guid>
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