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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>
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      <title>Transport Research International Documentation (TRID)</title>
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      <link>https://trid.trb.org/</link>
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      <title>Comparison of Smartphone-Based and Drone-Based Approaches for Assessing Road Roughness</title>
      <link>https://trid.trb.org/View/2190164</link>
      <description><![CDATA[Continuous road-pavement condition monitoring is essential to maintain the effectiveness and performance of road infrastructure. It also helps to optimize resource allocation and prioritization for pavement rehabilitation programs. The traditional methods that have been used for assessing road pavement condition are high cost and time consuming. Contrary to conventional methods, low-cost and new emerging technologies such as smartphones and drones can be used. The study aims to investigate the merits of using two different types of device for assessing road roughness: the smartphone as a response-type and the drone as a non-contact-type device. To this end, firstly, linear vertical acceleration data is collected by using a smartphone that is mounted on a car dashboard. Then, the collected data is used for calculating vertical displacement data using a fast Fourier transform. The displacement data is used for calculating international roughness index (IRI) as a measure of road roughness. Secondly, a drone flies over the studied road to construct a 3D model, extract the longitudinal profile, and eventually calculate the accurate IRI values of the road. Finally, the results of the approaches above will be compared with the results of a road surface profiler (RSP) as a reference method. Although the results reveal a significant correlation (above 0.8) of both methods with the RSP method, from an operational point of view, the smartphone was more cost and time effective, and also an easy-to-use approach for the purpose.]]></description>
      <pubDate>Tue, 06 Jun 2023 15:38:32 GMT</pubDate>
      <guid>https://trid.trb.org/View/2190164</guid>
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    <item>
      <title>ENGINE DAMAGE TO A NASA DC-8-72 AIRPLANE FROM A HIGH-ALTITUDE ENCOUNTER WITH A DIFFUSE VOLCANIC ASH CLOUD</title>
      <link>https://trid.trb.org/View/755314</link>
      <description><![CDATA[This paper presents analysis of volcanic ash plume, ash particles collected in cabin air heat exchanger filters and removed from engines, trajectory from satellites, and data from onboard instruments and engine conditions relating to the National Aeronautics and Space Administration (NASA) research airplane that flew through a volcanic ash cloud. The NASA DC-8 airborne sciences research airplane flew through a diffuse volcanic ash cloud of the Mt. Hekla volcano, inadvertently, in February 2000 during a flight from Edwards Air Force Base to Kiruna, Sweden. Sensitive research experiments and instruments detected the ash plume even though the ash plume was not visible to the flight crew.  Post-flight visual inspections and in-flight performance checks did not reveal any damage to the engine first-stage fan blades or to the airplane.  However, detailed examinations conducted subsequently revealed clogged turbine cooling air passages.  The engines were removed and overhauled.]]></description>
      <pubDate>Tue, 12 Apr 2005 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/755314</guid>
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    <item>
      <title>STATISTICAL STUDIES ON DYNAMIC ZONES OF PROTECTION DURING HORIZONTAL EVASIVE MANEUVERS</title>
      <link>https://trid.trb.org/View/52172</link>
      <description><![CDATA[The report deals with theoretical studies and arithmetical simulations in the field of dynamic zones of protection during horizontal evasive maneuvers for avoiding midair collisions.  The airborne navigation system consists of a VOR/DME receiving equipment and a simple RNAV unit.  During a flight on a VOR radial the pilot is requested by a controller to make a track leg change to an impromptu waypoint as soon as a selected distance will be indicated on the DME instrument.  The zones of protection at the end of the evasive turn and during the flight to the waypoint are symbolized by means of 95 per cent ellipses.  The influences of the VOR/DME errors, the flight technical errors and the evironmental conditions on the position, the shape and the size of the ellipses are investigated analytically.]]></description>
      <pubDate>Sat, 31 May 2003 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/52172</guid>
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    <item>
      <title>AIRCRAFT FLIGHT CONTROL ACTUATION SYSTEM DESIGN</title>
      <link>https://trid.trb.org/View/466759</link>
      <description><![CDATA[This book describes the earliest flight control actuation systems and their progression from aerodynamic tab-controlled surfaces to mechanical-input-controlled hydraulic actuators to electrical-input-controlled fly-by-wire actuation systems (both hydraulic and electromechanical). The book also covers: Alternate Command Systems; Electrically Powered (Power-By-Wire) Actuation Systems; Flight Control System Design Requirements; Applicable Specifications and Advisory Documents; Power Control Unit and Power-Drive Unit Design Guidelines; Dynamic Performance and Response; PCU Assembly and Installation; and Quality Assurance.]]></description>
      <pubDate>Tue, 04 Feb 1997 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/466759</guid>
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    <item>
      <title>AERIAL PROFILING OF TERRAIN SYSTEM</title>
      <link>https://trid.trb.org/View/196987</link>
      <description><![CDATA[Since 1974, the U. S.  Geological Survey (USGS) has been developing the Aerial Profiling of Terrain System (APTS) for measuring stream-valley cross sections and profiles, older map reliability testing, and producing control for topographic maps.  The system consists of an inertial measuring unit (IMU), a laser tracker, a laser profiler, a video imaging system, supporting electronics, and a computer.]]></description>
      <pubDate>Wed, 29 Feb 1984 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/196987</guid>
    </item>
    <item>
      <title>OPTIMAL GUIDANCE AND CONTROL FOR INVESTIGATING AIRCRAFT NOISE-IMPACT REDUCTION</title>
      <link>https://trid.trb.org/View/75535</link>
      <description><![CDATA[A methodology for investigating the reduction of community noise impact is reported. This report is concerned with the development of two models to provide data: a guidance generator and an aircraft control generator suitable for various current and advanced types of aircraft. The guidance generator produces the commanded path information from inputs chosen by an operator from a graphic scope display of a land-use map of the terminal area. The guidance generator also produces smoothing at the junctions of straight-line paths.The aircraft control generator determines the optimal set of the available controls such that the aircraft will follow the commanded path. The solutions for the control functions are given and shown to be dependent on the class of aircraft to be considered, that is, whether the thrust vector is rotatable and whether the thrust vector affects the aerodynamic forces. For the class of aircraft possessing a rotatable thrust vector, the solution is redundant; this redundancy is removed by the additional condition that the noise inpact be minimized. Information from both the guidance generator and the aircraft control generator is used by the footprint program to construct the noise footprint.]]></description>
      <pubDate>Wed, 31 Oct 1979 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/75535</guid>
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    <item>
      <title>FEASIBILITY AND COST EFFECTIVENESS OF AIRBORNE TIRE PRESSURE INDICATING SYSTEMS</title>
      <link>https://trid.trb.org/View/83116</link>
      <description><![CDATA[The cost-effectiveness and feasibility of airborne tire pressure indicating systems are evaluated for potential application to modern air carrier transports having 6, 10, and 18 wheels. Both wheel mounted pressure readout gauges and devices and cockpit tire pressure warning indicators are studied. Typical wheel mounted readout devices and eleven conceptual cockpit indicating systems are discussed. Information on accuracy, temperature compensation requirements, weight, installation cost, system cost, and system maintenance cost is provided. Each cockpit system is evaluated against important design criteria which require that cockpit systems cause no false warnings and that each system be capable of being tested periodically to determine its ability to detect a low pressure tire when it occurs. A study of tire failures is made for 1973-1976 identifying rate of tire failures and aircraft damage costs resulting from tire failures. The study presents data that shows that 65% of airframe damage cost is related to underinflation - induced or related tire failures which may be avoided by a properly designed tire pressure indicating system. Average airframe damage cost per departure for each study aircraft, based on actual airline data, is presented with comments on delay and cancellation costs. Aircraft damage costs and tire maintenance costs that may be avoided are compared to tire pressure indicating system life cycle costs to show that tire pressure systems are basically feasible, but marginally cost effective aircraft testing of promising systems is recommended. (Author)]]></description>
      <pubDate>Wed, 11 Jul 1979 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/83116</guid>
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    <item>
      <title>ILS GLIDEPATH: NEW DESIGNS FOR SEVERE SITES</title>
      <link>https://trid.trb.org/View/86936</link>
      <description><![CDATA[A fundamental new theory for the operation of the instrument landing system (ILS) glidepath is presented.  Simple new image array designs for use on severe sites are developed from this theory.  The design makes use of Schelkunoff's simple circle diagram technique and it allows the separate specification of the radiated fields and the ground requirement.  Two new glidepath arrays are particularly recommended from the many possible designs.  The new arrays have been thoroughly tested at model scale and on a particularly severe site at Sydney airport.  The approach also leads to a simpler setting up procedure which substantially improves performance.]]></description>
      <pubDate>Wed, 13 Jun 1979 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/86936</guid>
    </item>
    <item>
      <title>WIDE-APERTURE DIGITAL VOR</title>
      <link>https://trid.trb.org/View/86935</link>
      <description><![CDATA[Aircraft navigation through the United States and in many parts of the world today is based on guidance information supplied by very high frequency (VHF) omnidirectional range (VOR) facilities, usually in conjunction with colocated distance measuring equipment.  The objectives of an improved VOR would be a system that would significantly reduce magnitude of siting errors, provide greater accuracy and use digital techniques to simplify processing.  The wide-aperture digital VOR described has been developed to meet these objectives.  Its design is based on the crossed-pair interferometer principle where eight such pairs are energized succcessively by a set of pulses and phase shifts.  The time-multiplexed signal, detected by the aircraft receiver, is processed and simple digital computations are performed to determine the angular coordinates.  The performance improvements have been achieved by the combination of using a 275-ft antenna aperture, and the use of digital techniques to generate the ground-radiated navigational signals and to process them in the airborne processor.  Field tests of the feasibility model indicate it is a high performance system, capable of achieving an order of magnitude improvement in both site error reduction and in accuracy compared to present VOR systems.  The measured accuracies were 0.  11-degree standard deviation.]]></description>
      <pubDate>Wed, 13 Jun 1979 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/86935</guid>
    </item>
    <item>
      <title>ENVIRONMENTAL CONDITIONS AND TEST PROCEDURES FOR AIRBORNE ELECTRONIC/ELECTRICAL EQUIPMENT AND INSTRUMENTS</title>
      <link>https://trid.trb.org/View/84846</link>
      <description><![CDATA[Standard procedures and environmental test criteria for testing electronic equipment, electrical equipment, and instruments for the whole spectrum of aircraft from light general aviation aircraft and helicopters through the "Jumbo Jets" and SST categories of aircraft.]]></description>
      <pubDate>Fri, 11 May 1979 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/84846</guid>
    </item>
    <item>
      <title>GENERAL AVIATION FLIGHT INSTRUMENT DISPLAYS</title>
      <link>https://trid.trb.org/View/85043</link>
      <description><![CDATA[The basic criteria of ease of use and rapid failure detection have been applied to general aviation instrument designs.  Several suggestions can be made to improve the existing instrument standards by relocating the primary navigation and vertical speed indicators and by including the clock and magnetic compass in the standards.  Power supplies for instruments must not be designed to allow a single failure to jeopardize the airplane.  The general aviation airplane should have the same degree of care given to instrument and systems design as is given to the transport.  In fact, since these airplanes are typically flown by inexperienced pilots and since the systems often do not have redundant components, factors and systems engineering should play even greater roles.]]></description>
      <pubDate>Wed, 14 Mar 1979 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/85043</guid>
    </item>
    <item>
      <title>DESIGN CRITERIA FOR AIRCRAFT WARNING, CAUTION, AND ADVISORY ALERTING SYSTEMS</title>
      <link>https://trid.trb.org/View/85093</link>
      <description><![CDATA[An overabundance of warning, caution, and advisory alerts will exist in the cockpits of future commercial transport aircraft if current cockpit design trends are not altered. Coupled with this proliferation of alerts is a lack of correlation between alert-type applications and significance.  The potential for pilot saturation and/or confusion exists with these alerts.  A study was performed for the FAA to identify these problem areas and to develop design guidelines for alerting systems in new aircraft. Recommendations resulting therefrom include: 1) improve pilots' audio/visual environment by minimizing exposure to unnecessary alerts; 2) incorporate central alphanumeric alert readout devices; and 3) improve categorization and/or prioritization of alerts.]]></description>
      <pubDate>Wed, 14 Mar 1979 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/85093</guid>
    </item>
    <item>
      <title>COST-BENEFIT ANALYSIS OF A SIMULATOR TEST FOR PILOT SELECTION IN THE ROYAL AIR FORCE</title>
      <link>https://trid.trb.org/View/85047</link>
      <description><![CDATA[A research project, designed to test the feasibility of using a flight simulator to predict success in flying training is described.  The results of the research are discussed in terms of the manpower changes which would result from including an additional test into the current selection process.  The cost implications have been analyzed with the aid of two, purpose-built, computer models which give the capability of maximizing cost savings and testing the sensitivity of input assumptions.]]></description>
      <pubDate>Wed, 14 Mar 1979 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/85047</guid>
    </item>
    <item>
      <title>DEVELOPMENT OF STARTING POINTS FOR A SELECTIVE SUPPORT PROGRAM FOR CIVIL AVIONICS TECHNOLOGIES</title>
      <link>https://trid.trb.org/View/85099</link>
      <description><![CDATA[The present study represents an analysis of the present state of the West German avionics industry and is mainly designed to answer the question whether and in which area the technological development of the German civil avionics industry can be meaningfully furthered by systematic government support.  The relevant information was obtained in interviews with experts in Germany and other countries.]]></description>
      <pubDate>Wed, 14 Mar 1979 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/85099</guid>
    </item>
    <item>
      <title>JEPPESEN CHARTING FOR AREA NAVIGATION</title>
      <link>https://trid.trb.org/View/87774</link>
      <description><![CDATA[The most sophisticated NVAV systems in existence today are the ones which can utilize either latitude and longitude or bearing and distance from the station as inputs for navigation.  These Automated Airborne Navigation Systems offer a means of placing some information in the cockpit in a manner such that its application can be automated to a high degree.  The heart of the system for the pilot is the Control Display Unit, or CDU, with a complete alpha/numeric keyboard.  Contained within the Automated Navigation System is a Flight Data Storage Unit, or FDSU, which contains all the navigational data in computer language on a magnetic tape or disc.]]></description>
      <pubDate>Wed, 14 Mar 1979 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/87774</guid>
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