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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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    <item>
      <title>INTRUSION ALARM GOES HIGH TECH</title>
      <link>https://trid.trb.org/View/481682</link>
      <description><![CDATA[Work-zone-related deaths cost plenty -- in terms of liability ($2 million) to $3 million each, in many cases) and in families' suffering. Worker injuries are just as devastating. Technology provides at least a partial solution with work-zone intrusion alarm systems. The alarms alert drivers to the fact that they have crossed into a work space. Some systems trigger the vehicle's radar detector. Developed in conjunction with the FHWA's SHRP program, recent tweaking to improve the systems includes digitally encoded, microwave-based technology.]]></description>
      <pubDate>Tue, 18 Mar 1997 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/481682</guid>
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      <title>DESIGN, CONSTRUCTION, TEST AND EVALUATION OF A FREQUENCY SCANNING RADIOMETER FOR MEASURING OIL SLICK THICKNESS</title>
      <link>https://trid.trb.org/View/422134</link>
      <description><![CDATA[MIT Lincoln Laboratory has proposed the concept of using a frequency scanning radiometer to sample multiple points across a frequency band, thus resolving the problem of ambiguities in oil thickness estimation. A laboratory-prototype FSR capable of scanning over Ka-band (26 - 40 GHz) was designed, built, and tested. The FSR was used in laboratory proof-of-principle testing to (1) measure uniform thickness oil layers under various ambient weather conditions (day, night, clear, cloudy, drizzle, and snow) and different oil types, and (2) measure the phenomenology of non-uniform thickness oil layers and emulsions. Comparisons of measured data sets with theoretical predictions demonstrated that the expected response of oil is consistent regardless of oil type or ambient weather condition. Comparisons of uniform oil layer measurements and non-uniform measurements with theoretical predictions indicate that the radiometric brightness temperature (T[raised B]) of the oil above that of water is a function of the percentage of that thickness of oil within the antenna field-of-view. Water/oil emulsions were measured and have a higher T[raised B]) than a uniform layer of pure oil at the same thickness. Recommendations for FSR modifications and improvements, as well as future collection work are included.]]></description>
      <pubDate>Mon, 19 Jun 1995 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/422134</guid>
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      <title>RF/ID IN TRANSPORTATION. ANALYZING RF OPTIONS TO AID IN TRAFFIC ANALYSIS, TOLL COLLECTION, AND OTHER REAL-WORLD APPLICATIONS</title>
      <link>https://trid.trb.org/View/371061</link>
      <description><![CDATA[The development of radio frequency-based automatic vehicle identification systems has created many opportunities to improve the efficiency of road transport operations. This paper briefly describes systems that are currently available and lists some potential applications for automatic vehicle identification equipment. In addition, two specific applications of the technology are described in more detail: a VHF radio system for measurement of vehicle travel time in Sydney, Australia, and UHF/microwave systems for electronic toll collection.]]></description>
      <pubDate>Tue, 26 Jan 1993 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/371061</guid>
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    <item>
      <title>OPERATIONAL DEMONSTRATION AND FLIGHT TEST OF THE MICROWAVE LANDING SYSTEM (MLS) AT THE MIAMI/TAMIAMI, FLORIDA AIRPORT</title>
      <link>https://trid.trb.org/View/304987</link>
      <description><![CDATA[At the request of the Microwave Landing System (MLS) Program Office, the Federal Aviation Administration (FAA) Technical Center conducted an operational demonstration and flight test of the MLS at Miami/Tamiami, Florida Airport.  The demonstration/flight test was conducted in conjunction with an MLS seminar jointly sponsored by U.S. Department of Transportation, FAA, and Transport Canada Aviation Group. The Technical Center's MLS test bed, consisting of a 1.5 degree beamwidth elevation station and a 2 degree beamwidth azimuth station, was transported to, and temporarily installed at the Miami/Tamiami Airport on runway 9R, collocated with the commissioned instrument landing system (ILS).  Additionally, an E-Systems preproduction model precision distance measuring equipment (DME/P) transponder was also installed adjacent to the runway 9R localizer equipment shelter.  On March 29, 1989, seven 1-hour demonstration and data collection flights were flown for over 60 aviation, industry, and U.S. and international Government attendees.  By careful siting of the MLS on runway 9R, proportional MLS signal coverage was also obtained in the approach regions of runways 9L and 13.  By utilizing Technical Center designed and fabricated MLS area navigation (RNAV) computer on board the demonstration aircraft, precision approaches were flown not only to runway 9R, but also to runways 9L and 13.  This demonstrated the tremendous flexibility and operational capability of MLS. The MLS signal-in-space on runway 9R met category 2 ILS tolerances.  No degredation of the ILS performance due to the MLS collocation was detected during this demonstration.]]></description>
      <pubDate>Mon, 30 Apr 1990 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/304987</guid>
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    <item>
      <title>SURVEY OF BRIDGE DECKS WITH GROUND-PENETRATING RADAR - A MANUAL. FINAL REPORT</title>
      <link>https://trid.trb.org/View/267758</link>
      <description><![CDATA[This manual has been prepared to facilitate the use of ground-penetrating radar (GPR) in the bridge inspection program of the Virginia Department of Highways and Transportation.  It briefly discusses the basic principle of GPR, and its application in the nondestructive insepction of bridge decks for delaminations in the reinforced concrete. It then provides guides on the survey procedure, the operation of a microwave radar system, and the interpretation and the quantification of radar results. (Author)]]></description>
      <pubDate>Fri, 31 Jul 1987 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/267758</guid>
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    <item>
      <title>ESTIMATES OF MAXIMUM ELECTRIC FIELD STRENGTHS IN THE AUTOMOBILE ENVIRONMENT</title>
      <link>https://trid.trb.org/View/89197</link>
      <description><![CDATA[Strong electromagnetic (EM) energy sources up into the microwave range are examined and estimates are made of maximum EM field conditions to which automobiles could be exposed. The results are meant to alert automotive engineers to potentially hazardous EM radiation that might upset on-board electronic control devices.]]></description>
      <pubDate>Wed, 17 Oct 1979 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/89197</guid>
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      <title>PRESENT STATUS OF THE BRIDGE ICE DETECTION PROGRAM AT FHWA</title>
      <link>https://trid.trb.org/View/86419</link>
      <description><![CDATA[This paper discusses the need for an effective ice detection system for bridges, and outlines an early evaluation program that has led to the selection of a spot ice detector for further testing.  This small detector is installed flush with the surface of a pavement and, with its associated electronics package, is capable of transmitting surface conditions to a remote location over a telephone or radio link.  The advantages of an area ice detector are discussed and results to date in the development of a microwave radiometer for detection of surface condition are presented. /Author/]]></description>
      <pubDate>Wed, 13 Jun 1979 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/86419</guid>
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    <item>
      <title>RECOGNITION AND IDENTIFICATION</title>
      <link>https://trid.trb.org/View/86169</link>
      <description><![CDATA[Techniques for recognizing the presence or potential development of landslides and the observable features that aid in identifying the types of slope movements and their probable causes are discussed.  The techniques include (a) a review of topographic maps and geologic, pedologic, and engineering reports and maps; (b) the analysis of aerial photography and other forms of aerial images; and (c) preliminary field reconnaissance surveys.  These three techniques complement one another and together form the basis of the preliminary analysis in a landslide investigation.  The use of aerial techniques for evaluating landslides is emphasized because of their proven value and the unique advantages they offer.  Aerial techniques can provide a three-dimensional overview of the terrain from which the interrelations existing among slope, drainage, surfce cover, rock type and sequence, and human activities on the landscape can be viewed and evaluated.  In addition, the availability of new types of aerial imagery, including satellite, infrared, radar, and microwave radiometry, extend the advantages of this technique.]]></description>
      <pubDate>Sat, 26 May 1979 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/86169</guid>
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      <title>THE DEVELOPMENT OF A MICROWAVE RADIOMETER FOR USE AS A HIGHWAY ICE DTECTOR</title>
      <link>https://trid.trb.org/View/81841</link>
      <description><![CDATA[The program objective was to develop a system capable of detecting snow, ice, frost, or slush over a highway bridge deck area greater than 4 x 2 feet (1.2 x 0.6 m) and generate a valid alarm signal to warn motorists of a hazard.  The detection system selected was a microwave radiometer operating at 10 GHz which continuously samples a reference noise source and internal amplifier noise to provide measurement corrections of radiated power received from the road surface being observed.  Principal radiometer components are: rectangular horn antenna; sensitive receiver; and signal processor/alarm unit.  The successive program phases were: design optimization and system tradeoffs; breadboard model laboratory and field tests; and prototype model design, fabrication and test.  Test results on asphalt and concrete roadway simulators, as well as actual asphalt roads, correlated with previously published radiometric temperatures for similar surfaces.  The following road conditions were detectable: dry/warm; dry/cold; wet; slush; ice layer (0.1 cm minimum); and snow layer (1 cm minimum).  All road hazard detection objectives were met except for frost detection.  Descriptions of recommended additional effort are presented, including detailed evaluation of the prototype model; advanced alarm logic; self-test techniques; and a scanning antenna to cover increased road areas.  /FHWA/]]></description>
      <pubDate>Thu, 12 Apr 1979 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/81841</guid>
    </item>
    <item>
      <title>HELPING SPEEDERS BEAT THE RADAR RAP</title>
      <link>https://trid.trb.org/View/79320</link>
      <description><![CDATA[In recent years, some complications have entered into the use of radar for catching speeders.  Since about 1974, when high quality radar detectors first came on the market, there has been a "cold war" between designers of police radar equipment used by speeding motorists trying to evade being ticketed.  For instance, until late 1975, all police radar operated at 10.5-10.55 GHZ (x-brand); therefore, detectors were designed to be sensitive just to this range.  Then, 24.05-24.15 GHZ (k-brand) radar was developed, only to be followed by "dual-brand" detectors.  In turn, to get around the use of these detectors as well as the fact that detectors have a wider range (2 miles) then the radar itself (1/2 mile), on/off "keyed" radar which emit no microwave beam until an approaching vehicle has been visually sighted has been developed.  Still another gambit is the deployment along expressways of "dummy" radar transmitters operating continuously on the police radar frequencies which are (unbeknownst to the motorist with a detector) unattended. This "cold war" is likely to continue since state and local laws against the use of detectors have not held up in court. From the viewpoint of the law-abiding motorists, there is the problem that radar equipment malfunction and/or inexperience on the part of the operator may lead to incorrect target identification and the ticketing of innocent motorists.  Still another problem is the current lack of performance standards for police radar equipment, although this will be eventually rectified as the NHTSA has recently announced that standards will be developed by the NBS Law Enforcement Standards Laboratory.]]></description>
      <pubDate>Thu, 12 Oct 1978 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/79320</guid>
    </item>
    <item>
      <title>MEASURING SOIL MOISTURE WITH AN AIRBORNE IMAGING PASSIVE MICROWAVE RADIOMETER</title>
      <link>https://trid.trb.org/View/60458</link>
      <description><![CDATA[Short of exhaustive field sampling, no dependable method for gathering regional soil moisture data presently exists. Passive microwave remote sensing technology has the ability to provide areally extensive information on near-surface soil moisture condition.  Experiments conducted with an imaging passive microwave radiometer on the West Side, San Joaquin Valley, California, indicate that a statistically highly significant linear correlation exists between image tone density and moisture content in the top 5 cm of the soil.  Further, this relationship may be seen to intensify somewhat when soils are subdivided by type and show a slightly stronger correlation for the less coarse of the two soil types present.  /Author/]]></description>
      <pubDate>Thu, 16 Feb 1978 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/60458</guid>
    </item>
    <item>
      <title>PROMISE OF AUTOMATIC VEHICLE IDENTIFICATION</title>
      <link>https://trid.trb.org/View/53017</link>
      <description><![CDATA[Automatic vehicle identification (AVI) technology, which permits fully automatic and unique identification of vehicles at specific interrogation points, offers potential benefits in many fields including fleet control, revenue collection, traffic operations, transportation planning, and safety and law enforcement.  Three technologies are currently being used for AVI: optical, microwave, and low power radio frequency.  All of the three technologies are currently being used in either operating systems or extensive field testing under operating conditions.  The first large scale application of AVI was in the railroad industry to identify automatically rolling stock.  The optical AVI techniques used have also been applied in automatic container identification and, in a limited scope application, in the operation of an automatic toll collection system.  Microwave AVI techniques have been tested successfully in containerization applications and are currently under test by a major toll road in revenue collection application.  Low power radio frequency AVI was tested extensively in the federally-sponsored Automatic Bus Identification Project and is being evaluated for nonstop toll collection application by toll agencies.  While the cost effectiveness of AVI will vary to a considerable extent with the technology used and the desired functional requirements, existing AVI technology can provide automatic unique identification of vehicles at a cost which can be justified in many applications.  As these applications are being developed, the rapid advances in computer and electronic technology which are inherent in AVI systems, will further reduce initial and operating costs of contemplated AVI systems.]]></description>
      <pubDate>Thu, 13 Oct 1977 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/53017</guid>
    </item>
    <item>
      <title>USEFULNESS OF IMAGING PASSIVE MICROWAVE FOR RURAL AND URBAN TERRAIN ANALYSIS</title>
      <link>https://trid.trb.org/View/53045</link>
      <description><![CDATA[In-depth ground truth data has been collected in conjunction with four microwave radiometer (MICRAD) flights.  Images were evaluated to determine their information content in studies of the cities of Lost Hills, Coalinga and Bakerfield, California.  Results indicate that passive microwave radiometers can yield accurate information for general land use maps.  In addition, the agricultural landscapes around Lost Hills and Coalinga were imaged.]]></description>
      <pubDate>Thu, 13 Oct 1977 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/53045</guid>
    </item>
    <item>
      <title>EVALUATION OF GEOPHYSICAL SYSTEMS FOR REMOTE SENSING OF SUBSURFACE CAVITIES IN KANSAS</title>
      <link>https://trid.trb.org/View/47249</link>
      <description><![CDATA[The Federal Highway Administration and its contractors, in cooperation with the State Highway Commission of Kansas (now the Kansas Department of Transportation), completed a field program in Kansas during 1971 to evaluate field geophysical systems for detecting subsurface cavities.  The geophysical systems included passive microwave radiometers, an impulse radar profiling instrument, and direct-current electrical resistivity.  Verification borings were completed in 1972 after analysis of the field data.  Field data and test borings are presented for 1 traverse line in Galena, Kansas, to characterize the research findings. Passive microwave radiometers are sensitive to soil moisture and often record the effects of surface drainage, groundwater seepage, and subtle topography.  The penetration of microwaves into soils, however, is limited, and the microwave radiometers are not well suited for detecting subsurface cavities.  The impulse radar profiling system produced a graphical output that closely approximated the subsurface soil, rock, water, and void interfaces.  The depth of radar penetration was limited to 8 ft (2.4 m) because of the presence of moist, clay-rich soils. Electrical resistivity proved to be the most useful technique for delineating subsurface materials. Geoelectrical soundings are well suited for locating conductive and insulative layers, but, because of the principle of equivalence, they may be unable to distinguish a water-filled cavity from another conductive subsurface zone.]]></description>
      <pubDate>Wed, 03 Nov 1976 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/47249</guid>
    </item>
    <item>
      <title>TIMING OF GROUND TRUTH ACQUISITION DURING REMOTE ASSESSMENT OF SOIL-WATER CONTENT</title>
      <link>https://trid.trb.org/View/37262</link>
      <description><![CDATA[Remote sensing of soil-water content is, at present, limited to the top few centimeters of soil. During a diurnal cycle the near-surface water content undergoes rather wide diurnal fluctuations. Data from five experiments on Avondale loam at Phoenix, Arizona, at various times of the year demonstrated that soil samples taken between 1100 and 1200 hours (MST) best represented the 24 hour average soil-water content. Also, the average of the daily maximum and minimum water contents closely approximated the 24 hour average. The data showed that time of sampling was an important criterion when obtaining ground truth in remote sensing of soil-water content.]]></description>
      <pubDate>Wed, 11 Aug 1976 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/37262</guid>
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