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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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    <item>
      <title>TRUCK OPERATIONS AND REGULATIONS ON URBAN FREEWAYS</title>
      <link>https://trid.trb.org/View/266842</link>
      <description><![CDATA[This study examines six general classes of truck regulations in terms of their impacts on urban freeway safety and traffic operations.  The truck restrictions and regulatory practices examined were: 1) Lane restrictions; 2) Time-of-day restrictions; 3) Speed restrictions; 4) Route restrictions; 5) Driver licensing and certification programs; and 6) Increased enforcement of existing regulations.  Of the six classes of regulations examined, only two appear capable of truck usage of producting any substantial improvement in the safety and operational aspects of truck usage of urban freeways in Texas.  Reduced speed limits, either for all vehicles or trucks only, appear to merit consideration on a trial basis.  In terms of long-term actions, the areas of driver licensing/training and incident management techniques should be emphasized.]]></description>
      <pubDate>Fri, 27 Aug 2004 21:13:09 GMT</pubDate>
      <guid>https://trid.trb.org/View/266842</guid>
    </item>
    <item>
      <title>MEASURING CAR USER BENEFITS ASSOCIATED WITH SOUTH AFRICAN URBAN FREEWAYS</title>
      <link>https://trid.trb.org/View/214411</link>
      <description><![CDATA[This paper deals with typical car user benefits achievable on South African urban freeways and discusses how these benefits can be identified and measured.  Several car trips on the M1 freeway through Johannesburg are compared with trips on the shortest alternative route, which follows several arterials through the city.  The relative values of the benefits were found to be as follows: vehicle operating cost savings, 38%; value of time saving, 37%; lower accident cost risk, 25%.  The net car user benefit obtained by travel on the freeway as compared to the alternative route is estimated to be almost 11 cents/km at 1981 prices.  (TRRL)]]></description>
      <pubDate>Wed, 25 Aug 2004 01:34:01 GMT</pubDate>
      <guid>https://trid.trb.org/View/214411</guid>
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      <title>REDUCING URBAN FREEWAY ACCIDENT FATALITIES WITH RAPID INCIDENT DETECTION</title>
      <link>https://trid.trb.org/View/538899</link>
      <description><![CDATA[Incident detection systems have the potential of reducing the time between the occurrence of accidents and the notification of emergency medical services, called the accident notification time.  Reductions in this time, in turn, may affect the number of fatalities.  A statistical analysis is conducted to determine the quantities of relationship between fatalities and the accident notification time on urban freeways.  Using this relationship, the impact of freeway incident detection systems on fatalities is estimated.  The economic benefits of fatality reduction are also derived.]]></description>
      <pubDate>Sun, 15 Sep 2002 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/538899</guid>
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      <title>NATURAL DIVERSION AT TEMPORARY WORK ZONE LANE CLOSURES ON URBAN FREEWAYS IN TEXAS. INTERIM REPORT</title>
      <link>https://trid.trb.org/View/374266</link>
      <description><![CDATA[This report documents the results of eleven field studies at temporary work zone lane closures on urban freeways in Texas. Traffic volume and travel time data were collected at each site on days when the lane closures were implemented at each site, and compared to data collected during the same time periods on similar days without a closure present.  Study results indicated a large amount of natural diversion occurred at those sites where normal freeway traffic demands far exceeded the available capacity through the work zone.  Entrance ramp volumes were lower a considerable distance upstream of the beginning of the queue, and were even lower at ramps located within the actual freeway queuing.  Exit ramps upstream  of the queue displayed very small changes in volumes.  In contrast, the first exit ramp motorists encountered after reaching the freeway queue consistently experienced significant increases in volumes.  As a result of the significant diversion occurring at each site, freeway queuing and delays tended to reach a threshold soon after the lane closure was enacted.  The queue and delay then remained at approximately that threshold level throughout the duration of the closure.  Also discussed in this report is the application of the findings from these studies to the QUEWZ computer model for estimating queuing and road user costs at freeway lane closures.]]></description>
      <pubDate>Fri, 07 Jun 2002 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/374266</guid>
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    <item>
      <title>CONSIDERATIONS IN THE APPLICATION OF FREEWAY COMPUTER SIMULATION MODELS TO PROJECT EVALUATION. INTERIM REPORT</title>
      <link>https://trid.trb.org/View/369160</link>
      <description><![CDATA[Improvements or new construction of freeways can benefit from tools to evaluate various design alternatives.  The use of a computer model to evaluate project alternatives is the most cost effective method, but often times the least understood.  This research study focuses on characteristics of and the process of choosing a freeway simulation model.  The input, output and possible applications of several freeway simulation models are listed and a case study highlighting the output from each model is presented for comparison.  Finally, a ranking of the freeway models is presented for particular applications.]]></description>
      <pubDate>Sun, 14 Apr 2002 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/369160</guid>
    </item>
    <item>
      <title>TRAVEL IMPACTS OF THE US-59 SOUTHWEST FREEWAY RECONSTRUCTION PROJECT IN HOUSTON. INTERIM REPORT</title>
      <link>https://trid.trb.org/View/369158</link>
      <description><![CDATA[This report documents the results and findings of a five-year study to monitor the travel impacts of the US-59 Southwest Freeway reconstruction project in Houston, Texas.  The monitoring effort included screen line traffic volume counts and travel time runs on the freeway, frontage roads, and alternative routes.  The results indicate drops in traffic volumes on the freeway primarily during the first phase of reconstruction and on the westbound frontage road throughout all three phases of reconstruction.  Only minor volume variations were observed on other routes in the corridor.  Travel times and average speeds in the corridor did not change significantly during reconstruction.  The impacts of the Southwest Freeway project were generally consistent with the impacts observed previously at other major urban freeway reconstruction projects in Texas.]]></description>
      <pubDate>Sun, 14 Apr 2002 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/369158</guid>
    </item>
    <item>
      <title>AN EVALUATION OF FREEWAY CAPACITY IN TEXAS. FINAL REPORT</title>
      <link>https://trid.trb.org/View/369159</link>
      <description><![CDATA[The current value of freeway capacity and the speed flow relationship have been questioned as a result of observations of flow rates much higher than 2,000 passenger cars per hour per lane (pcphpl) and the recent revision of the multi-lane highway chapter in the Highway Capacity Manual.  An analysis of freeway capacity in Texas found greater variability in free-flow flow rates and determined that queue discharge is the best estimate of maximum sustainable flow.  Average queue discharge flow rates averaged 2,225 pcphpl but were measured as high as 2,400 pcphpl for individual lanes.  Based on the analysis, a speed-flow model was developed and the maximum sustainable flow rate was determined to be 2,200 pcphpl, which is the value recommended for freeway capacity in Texas.]]></description>
      <pubDate>Sun, 14 Apr 2002 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/369159</guid>
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    <item>
      <title>COMPARISON OF THE SAFETY OF LIGHTING OPTIONS ON URBAN FREEWAYS</title>
      <link>https://trid.trb.org/View/426570</link>
      <description><![CDATA[Nationwide accident statistics show that more than 50% of fatal accidents occur during the hours of darkness.  Because only 25% of travel occurs during the same period, the fatality rate is about three times higher at night than during the day.  The installation of overhead lighting is a potential countermeasure to this nighttime accident problem.  However, this is expensive, and much of the research to date offers inconclusive results about its effect on highway safety.  This study compared the safety of continuously lighted urban freeways and urban freeways with interchange lighting only.  A freeway section with continuous lighting has overhead lighting at the interchanges and between the interchanges, as opposed to overhead lighting at the interchanges only.]]></description>
      <pubDate>Wed, 12 Jul 2000 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/426570</guid>
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    <item>
      <title>BIG TRUCKS: A SMALL PIECE OF A LARGER PROBLEM</title>
      <link>https://trid.trb.org/View/355745</link>
      <description><![CDATA[The Citizens League Board of Directors, responding to a perception that large trucks were a growing source of metropolitan freeway congestion, asked a committee to study how changes in truck traffic could reduce freeway accidents and congestion in the Twin Cities metropolitan area.  The committee focused primarily on interstate and other freeways in the metropolitan area.  Chapter 1 of this report presents the committee's findings on the role of large trucks in this metropolitan area's transportation system.  Chapter 2 presents the committee's conclusions and recommendations. Among the committee's principal conclusions are the following:  Large trucks do not significantly reduce Twin Cities freeway capacity, because they represent only a small part of total traffic.  Trucks are and will continue to be an important component of the movement of goods in the Twin Cities metropolitan area.  However, large trucks and autos operating in mixed, heavy traffic present safety and capacity problems that will compound in the future.  A number of small steps each promise to produce marginal improvements and, collectively, have the potential to alleviate future safety and congestion problems.  The committee's recommendations include the following:  1) The MnDOT's Metro Truck Management Program to divert trucks from congested corridors during peak travel times should be renewed and expanded.  2) The Minnesota Legislature should act on the results of the 1990 Minnesota highway cost-allocation study.  3) MnDOT and DPS should cooperatively develop and institute a more aggressive incident-management program in order to reduce delays and congestion.  4) MnDOT should conduct a thorough evaluation of peak-hour pricing on the most congested sections of metropolitan freeways and other major roads.  5) The Minnesota Senate and House Transportation committees should seek innovative ways to increase freight movement on the under-utilized capacity of railroads in the Twin Cities area.]]></description>
      <pubDate>Fri, 30 Jun 2000 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/355745</guid>
    </item>
    <item>
      <title>HUMAN FACTORS DESIGN CONSIDERATIONS FOR VARIABLE MESSAGE FREEWAY SIGNS</title>
      <link>https://trid.trb.org/View/389031</link>
      <description><![CDATA[A comprehensive human factors study was conducted to evaluate two technologies used in freeway signs: light emitting diode (LED) and shuttered fiber-optic variable message signs.  It was found that both technologies were acceptable for use on urban freeways. Additional research developed level of service and design criteria for variable message signs, based on the data collected in the human factors study.  This paper presents data on legibility distance, target value, and viewing comfort measured by observers as part of the comprehensive human factors study.]]></description>
      <pubDate>Thu, 16 Mar 2000 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/389031</guid>
    </item>
    <item>
      <title>URBAN FREEWAY RENEWAL</title>
      <link>https://trid.trb.org/View/542255</link>
      <description><![CDATA[FHWA examines the national issue of finding cost-effective and customer-sensitive methods to reconstruct freeway pavements. Details of a partnership between FHWA, the Transportation Research Board, and the California Department of Transportation (Caltrans) are provided. The partnership had two basic goals: (1) find a solution for I-710 and, in the process, identify the critical issues and provide a model for solving urban freeway problems, and (2) pioneer a new way of doing business within the highway community.]]></description>
      <pubDate>Mon, 14 Dec 1998 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/542255</guid>
    </item>
    <item>
      <title>URBAN FREEWAY TRAFFIC FLOW PREDICTION: APPLICATION OF SEASONAL AUTOREGRESSIVE INTEGRATED MOVING AVERAGE AND EXPONENTIAL SMOOTHING MODELS</title>
      <link>https://trid.trb.org/View/541976</link>
      <description><![CDATA[The application of seasonal time series models to the single-interval traffic flow forecasting problem for urban freeways is addressed.  Seasonal time series approaches have not been used in previous forecasting research.  However, time series of traffic flow data are characterized by definite periodic cycles.  Seasonal autoregressive integrated moving average (ARIMA) and Winters exponential smoothing models were developed and tested on data sets belonging to two sites: Telegraph Road and the Woodrow Wilson Bridge on the inner and outer loops of the Capital Beltway in northern Virginia.  Data were 15-min flow rates and were the same as used in prior forecasting research by B. Smith.  Direct comparisons with the Smith report findings were made and it was found that ARIMA (2, 0, 1)(0, 1, 1) at a lag of 96 (daily period) and ARIMA (1, 0, 1)(0, 1, 1) at a lag of 96 (daily period) were the best-fit models for the Telegraph Road and Wilson Bridge sites, respectively.  Best-fit Winters exponential smoothing models were also developed for each site.  The single-step forecasting results indicate that seasonal ARIMA models outperform the nearest-neighbor, neural network, and historical average models as reported by Smith.]]></description>
      <pubDate>Mon, 14 Dec 1998 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/541976</guid>
    </item>
    <item>
      <title>INVESTIGATION OF FREEWAY INCIDENT CHARACTERISTICS AND THEIR INFLUENCE IN PLANNING AN INCIDENT MANAGEMENT PROGRAM</title>
      <link>https://trid.trb.org/View/541876</link>
      <description><![CDATA[Nonrecurrent congestion caused by highway incidents is a major concern for transportation agencies and millions of road users in most metropolitan areas in the United States.  Incidents account for 60% of congestion-induced delay.  As a low-cost approach to incident management, freeway service patrol programs have gained wide popularity.  However, information on freeway incident characteristics is limited.  In the current paper, incident data recorded by the Hoosier Helper program in northwest Indiana is analyzed.  The distributions of incident frequency and clearance time by incident type and lateral location are reported.  The variation of incident rate with time of the day is examined, and the influence of various factors affecting the frequency and clearance time of incidents is explored.  Recommendations are made to improve the freeway service patrol program, based on the incident data analyzed. The information provided in this study may be useful for planning similar patrol programs in other metropolitan areas in Indiana and other states.]]></description>
      <pubDate>Wed, 02 Dec 1998 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/541876</guid>
    </item>
    <item>
      <title>FREEWAY SERVICE PATROLS: A STATE OF THE PRACTICE</title>
      <link>https://trid.trb.org/View/541874</link>
      <description><![CDATA[Freeway service patrols have been cited as one of the most effective elements of an incident management program for reducing incident detection time and incident duration.  Service patrol programs utilize roving vehicles to patrol congested and high incident sections of urban freeways.  The state of the practice of freeway service patrol programs in the United States is documented in this paper.  A telephone survey was conducted with managers of 53 freeway service patrols in 22 states. Approximately 74% of the surveyed service patrols are sponsored exclusively by public agencies.  Approximately 47% of the surveyed patrols are sponsored exclusively by Department of Transportations; 6% are sponsored exclusively by police agencies; and 21% are sponsored by multiple public agencies. Approximately 34% of the patrols receive federal support funding.  Finally, 27% of the patrols operate with private funding sources.  Service patrol hours of operation vary from program to program, with the most common being coverage of the weekday a.m. and p.m. peak periods.  Approximately 70% of the surveyed agencies own and operate their own vehicles, whereas 26% contract with private tow companies to provide drivers and vehicles.  Benefits associated with service patrols are typically quantified by multiplying a value of time by the estimated delay reduction provided by the service patrol in vehicle-hours.  Available benefit to cost analyses for 15 of the service patrols studied ranged from 2:1 to 36.2:1.  A contact list and recommendations for agencies interested in starting a new service patrol program are also included in this paper.]]></description>
      <pubDate>Wed, 02 Dec 1998 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/541874</guid>
    </item>
    <item>
      <title>FUZZY ART NEURAL NETWORK MODEL FOR AUTOMATED DETECTION OF FREEWAY INCIDENTS</title>
      <link>https://trid.trb.org/View/541877</link>
      <description><![CDATA[Pattern recognition techniques such as artificial neural networks continue to offer potential solutions to many of the existing problems associated with freeway incident-detection algorithms.  This study focuses on the application of Fuzzy ART neural networks to incident detection on freeways.  Unlike back-propagation models, Fuzzy ART is capable of fast, stable learning of recognition categories.  It is an incremental approach that has the potential for on-line implementation. Fuzzy ART is trained with traffic patterns that are represented by 30-sec loop-detector data of occupancy, speed, or a combination of both.  Traffic patterns observed at the incident time and location are mapped to a group of categories.  Each incident category maps incidents with similar traffic pattern characteristics, which are affected by the type and severity of the incident and the prevailing traffic conditions.  Detection rate and false alarm rate are used to measure the performance of the Fuzzy ART algorithm.  To reduce the false alarm rate that results from occasional misclassification of traffic patterns, a persistence time period of 3 min was arbitrarily selected.  The algorithm performance improves when the temporal size of traffic patterns increases from one to two 30-sec periods for all traffic parameters.  An interesting finding is that the speed patterns produced better results than did the occupancy patterns.  However, when combined, occupancy-speed patterns produced the best results.  When compared with California algorithms 7 and 8, the Fuzzy ART model produced better performance.]]></description>
      <pubDate>Wed, 02 Dec 1998 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/541877</guid>
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