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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>
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    <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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      <title>Offtracking: History, Analysis, and Simulation</title>
      <link>https://trid.trb.org/View/1787512</link>
      <description><![CDATA[Offtracking is the term used to describe the difference in path radii between the leading and trailing axle of a vehicle as it maneuvers around a turn. This phenomenon probably has been observed from the time multi-axle vehicles first were constructed. As vehicles, particularly articulated trucks, have become larger and longer, and the urban environment has become more compact and crowded, practical safety concerns relating to offtracking have increased. The geometric design of streets and highways, and of parking lots and trucking yards, will be affected by the maximum offtracking of vehicles using those facilities. In some accident investigations, offtracking is a primary consideration. Much of present offtracking analysis is based upon a “zero-speed” assumption. In other words, the magnitude of offtracking is computed simply as a kinematic problem, with no dynamic effects considered. When the problem is analyzed kinetically, offtracking outside the path of the preceding wheels (a kind of “oversteer”) can be computed, depending on vehicle speed and configuration. Effects of roadway superelevation and other three-dimensional terrain features can be included in computer simulations. This paper summarizes the history of offtracking analysis, presents a review of calculation methods in the literature, and details the speed-dependent nature of offtracking for two articulated heavy trucks, utilizing three-dimensional computer simulation.]]></description>
      <pubDate>Wed, 22 Jan 2025 09:33:57 GMT</pubDate>
      <guid>https://trid.trb.org/View/1787512</guid>
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    <item>
      <title>Estimation of trailer off-tracking using visual odometry</title>
      <link>https://trid.trb.org/View/1589420</link>
      <description><![CDATA[High-capacity vehicles have been shown to be highly effective in reducing emissions associated with road freight transport. However, the reduced manoeuvrability of long vehicles often necessitates the use of active trailer steering. Path-following trailer steering systems are very effective in this regard, but are currently limited to on-highway applications due to the manner in which trailer off-tracking is estimated. In this work, a novel trailer off-tracking measurement concept is introduced which is independent of wheel slip and ground surface conditions, and requires no additional sensor measurements or parameter data from the tractor. The concept utilises a stereo camera pair affixed to the trailer and a visual odometry-based algorithm to calculate off-tracking. The concept was evaluated in detailed simulation and full-scale vehicle tests, demonstrating its feasibility and highlighting some important characteristics. RMS measurement errors of 0.11–0.12 m (3.3–3.6%) were obtained in a challenging visual environment.]]></description>
      <pubDate>Mon, 01 Apr 2019 10:19:54 GMT</pubDate>
      <guid>https://trid.trb.org/View/1589420</guid>
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    <item>
      <title>Allowing 129,000-Pound Trucks on our Highways; What is the Cost? What are the Benefits?</title>
      <link>https://trid.trb.org/View/1494902</link>
      <description><![CDATA[The purpose of this paper is to provide engineering-based facts on allowing 129,000-pound trucks on  highway systems. The study investigates and documents the axle weight distribution and the operational characteristics of the 129,000-pound trucks and compares them to the characteristics of different truck types currently allowed on the highway system. The study then examines the implications of running these heavier trucks on highway systems covering four categories: offtracking requirements, impact on culvert and bridge structures, impact on pavement conditions, and impact on traffic safety. One of the major barriers is that local highway jurisdictions lack the necessary tools and resources to determine if their roads are capable of handling such truck loads. To address this, one of the study outcomes is a roadway analysis guide to assist local highway jurisdictions in evaluating route requests for trucks up to 129,000 pounds. The guide included different factors to consider when determining if roads are capable of withstanding heavier trucks. This research showed that allowing 129,000-pound trucks on highway systems, including local highways, provides a better utilization of the highway networks and an effective method to extend the life of roadways. Also, the research showed that, to comply with the Federal Bridge Formula, the 129,000-pound trucks distribute their weight across more axles leading to decreased axle loads on the roadway. This study specifically was conducted based on the the state of Idaho highway system.]]></description>
      <pubDate>Fri, 23 Feb 2018 16:27:33 GMT</pubDate>
      <guid>https://trid.trb.org/View/1494902</guid>
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    <item>
      <title>Kinematic Analysis of Tractor-Semitrailer with Split Fifth Wheel Coupling During Low Speed Turning Maneuvers</title>
      <link>https://trid.trb.org/View/1461636</link>
      <description><![CDATA[Over the years, commercial vehicles, especially tractor-semitrailer combinations have become larger and longer. With the increasing demand for their accessibility in remote locations, these vehicles face the problem of off-tracking, which is the ensuing difference in path radii between the front and rear axles of a vehicle as it maneuvers a turn. Apart from steering the rear axle of the semitrailer, one of the feasible ways of mitigating off-tracking is to shift the fifth wheel coupling rearwards. However, this is limited by the distribution of the semitrailer’s load between the two axles of the tractor; any rearward shift of the fifth wheel coupling results in the reduction of the total static load on the tractor’s front axle and hence available traction. This may in turn lead to directional instability of the vehicle. In the present work, a new model of the fifth wheel coupling is proposed which the authors call Split fifth wheel coupling (SFWC). Here, unlike the Conventional fifth wheel coupling (CFWC), the point of load transfer from the semitrailer to the tractor and the point of articulation are separated by a certain distance. A comparative study of the kinematic analysis for the vehicle combination with CFWC and SFWC is discussed in this paper. It is observed that the latter noticeably reduces off-tracking when compared to the vehicle with CFWC for a tractor-semitrailer combination of similar dimensions.       ]]></description>
      <pubDate>Wed, 17 May 2017 10:52:29 GMT</pubDate>
      <guid>https://trid.trb.org/View/1461636</guid>
    </item>
    <item>
      <title>Offtracking Calculation Charts for Trailer Combinations: Offtracking, Turning Track Widths and Curb Radii for Singe-Unit Vehicles and Trailer Combinations on Turns of Various Degrees and Radii</title>
      <link>https://trid.trb.org/View/1307315</link>
      <description><![CDATA[No abstract available.]]></description>
      <pubDate>Thu, 01 May 2014 12:00:57 GMT</pubDate>
      <guid>https://trid.trb.org/View/1307315</guid>
    </item>
    <item>
      <title>On optimal recovery from terminal understeer</title>
      <link>https://trid.trb.org/View/1302127</link>
      <description><![CDATA[This paper addresses the problem of terminal understeer and its mitigation via integrated brake control. The scenario considered is when a vehicle enters a curve at a speed that is too high for the tyre–road friction limits and an optimal combination of braking and cornering forces is required to slow the vehicle down and to negotiate the curve. Here, the driver commands a step steering input, from which a circular arc reference path is inferred. An optimal control problem is formulated with an objective to minimize the maximum off-tracking from the reference path, and two optimal control solutions are obtained. The first is an explicit analytical solution for a friction-limited particle; the second is a numerically derived open-loop brake control sequence for a nonlinear vehicle model. The particle solution is found to be a classical parabolic trajectory associated with a constant acceleration vector of the global mass center. The independent numerical optimization for the vehicle model is found to approximate closely the kinematics of the parabolic path reference strategy obtained for the particle. Using the parabolic path reference strategy, a closed-loop controller is formulated and verified against the solution from numerical optimization. The results are further compared with understeer mitigation by yaw control, and the parabolic path reference controller is found to give significant improvement over yaw control for this scenario.]]></description>
      <pubDate>Thu, 27 Mar 2014 21:45:29 GMT</pubDate>
      <guid>https://trid.trb.org/View/1302127</guid>
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    <item>
      <title>Simplified Model of Truck Braking and Handling: A User's Manual for The Low-Speed and High-Speed Offtracking Models, The Straight Line Braking Model, The Static Roll Model, The Steady Turn Model (Handling), The Rearward Amplification Model, The Brake Temperature Model</title>
      <link>https://trid.trb.org/View/1261130</link>
      <description><![CDATA[The Simplified Models discussed in this manual were developed by the University of Michigan Transportation Research Institute (UMTRI) through support provided by the Motor Vehicle Manufacturers Association (MVMA).  This User's Manual presents general and specific instructions for using these particular Simplified Models.  The intent of this manual is to provide the information necessary to operate the Simplified Models in the IBM PC environment.]]></description>
      <pubDate>Wed, 04 Sep 2013 17:17:01 GMT</pubDate>
      <guid>https://trid.trb.org/View/1261130</guid>
    </item>
    <item>
      <title>A numerical control algorithm for a B-double truck–trailer with steerable trailer wheels and active hitch angles. Part 2: Reversing</title>
      <link>https://trid.trb.org/View/1251820</link>
      <description><![CDATA[The authors have previously proposed a solution to the twin problems of wheel scuffing and off-tracking of B-double truck–trailer vehicles thereby reducing tyre wear and environmental damage as well as improving maneuverability. The solution to the scuffing problem requires that trailer axles in excess of one per trailer must have steerable wheels. However, if all trailer wheels are steerable, then the off-tracking problem can also be solved. The previous work devised an algorithm for a B-double in forward motion, whereby an on-board computer would be used to calculate the correct wheel and hitch angles and a control system would implement these angles.The purpose of the present technical note is to complete the study of a numerical algorithm for navigating a B-double truck–trailer vehicle by considering travel in the reverse direction. In this case the angle of the front wheels of the truck must also be controlled by the on-board computer. The algorithm for determining the effective angle of the truck’s steerable wheels is derived using an innovative combination of vector geometry and calculus and completes the total control system for these B-double vehicles.The paper concludes with a simulation study of the control algorithm demonstrating its versatility for reversing along twisting paths and effectiveness in reducing off-tracking.]]></description>
      <pubDate>Mon, 24 Jun 2013 10:58:55 GMT</pubDate>
      <guid>https://trid.trb.org/View/1251820</guid>
    </item>
    <item>
      <title>Effects of Roadway Geometric Features on Low-Speed Turning Maneuvers of Large Vehicles</title>
      <link>https://trid.trb.org/View/1124471</link>
      <description><![CDATA[Vehicle turning maneuver is a major design control in roadway alignment, pavement and the placement of curbs at highway intersections. Geometric features, such as the sharper curvature at turning roadways have significant effects on turning maneuverability of vehicles. Due to their wider and longer wheelbases, large vehicles have much more pronounced offtracking and occupy greater swept-path widths. This often creates complex driving operations when large vehicles turn at intersections. The turning maneuvers of large vehicles not only determine roadway design, but also influence the safety and efficiency of intersection operations. Studying turning maneuvers mainly consists of analyzing vehicle turning paths and steering operations. This study presents a computational approach that can simulate vehicle turning maneuverability for given roadway alignments, and also checks for coincidence with design standards. This study also presents field experiments involving tractor-semitrailer truck and bus on roadways with different geometric features. The turning paths of wheels and steering wheel operations were recorded simultaneously. Data from field experiments of different turning angles and roadway geometric features are compared with simulated results of computational approach. This study also analyzes the effects of curve radius and geometric features on turning maneuvers. The precise analysis of vehicle turning maneuvers, including turning paths, swept widths, and steering operations, could help roadway and pavement engineers improve traffic safety and efficiency.]]></description>
      <pubDate>Fri, 16 Dec 2011 14:47:14 GMT</pubDate>
      <guid>https://trid.trb.org/View/1124471</guid>
    </item>
    <item>
      <title>Optimized Design of Concrete Curb under Off Tracking Loads</title>
      <link>https://trid.trb.org/View/894557</link>
      <description><![CDATA[Most research studies in the portland cement concrete (PCC) pavement area focused on addressing distresses related to pavement structure itself. As a result, the design and construction of other structural elements of the concrete curb and curb and gutter (CCCG) system have been overlooked and not much research has been done in this area. Visual inspection of damaged CCCG systems was conducted in the field. All damaged CCCG systems were the Texas Department of Transportation (TxDOT) Type II system and almost all damaged CCCG systems were found at U-turn curbs due to excessive off tracking of traffic. Although geometric changes of the curb design are the fundamental solutions for the off tracking failure, such changes are not feasible in most cases due to economic and space limitations. Extensive finite element analysis was performed based on the new U-turn curb design of the TxDOT Houston district. The horizontal loading is the most critical loading condition to evaluate the structural adequacy of a CCCG system. The structural capacity of CCCG can be enhanced by increasing the curb width and/or by inserting the curb dowel further from the traffic face of CCCG. The use of the new U-turn curb design from the TxDOT Houston district is highly recommended for areas affected by the off tracking of heavy vehicles. It is recommended to position the curb dowel further from the traffic face of a CCCG system for better performance when the new U-turn curb design is applied. The use of an epoxy-grouted curb dowel is also recommended instead of a manually inserted straight dowel bar to ensure better bond performance between dowel bar and concrete in a CCCG system.]]></description>
      <pubDate>Mon, 20 Jul 2009 08:54:05 GMT</pubDate>
      <guid>https://trid.trb.org/View/894557</guid>
    </item>
    <item>
      <title>Effect of Multi-Axle Steering on Off-Tracking and Dynamic Lateral Response of Articulated Tractor-Trailer Combinations</title>
      <link>https://trid.trb.org/View/849906</link>
      <description><![CDATA[Linear yaw plane models are used to study multi-axle steering systems with a tractor and up to three full trailers to investigate how off-tracking phenomena are affected by additional steering on lateral responses during lane-change maneuvers and 90-degree turns. Linear stability analysis is used to study the dependence of critical speed(s) for lateral stability of the steered trailer axle(s)' location(s). Stability is reduced by non-steered trailer(s) addition. Drastic reduction of yaw and slip velocities, lateral forces, and high- and low-speed off-tracking, as well as the concomitant directional stability increase, results, however, from trailer steering.]]></description>
      <pubDate>Mon, 31 Mar 2008 08:03:30 GMT</pubDate>
      <guid>https://trid.trb.org/View/849906</guid>
    </item>
    <item>
      <title>Steering Control for Advanced Guideway Bus System with All-Wheel Steering System</title>
      <link>https://trid.trb.org/View/806467</link>
      <description><![CDATA[This article proposes a steering control strategy for articulated buses equipped with an all-wheel steering system to eliminate off-tracking.  In this system, the center of each axle passes through the same locus, which is similar to the operation of trains.  This control system was validated by means of a numerical simulation, using a vehicle dynamics model and some experiments with a scaled vehicle model.  The proposed control system was confirmed to be effective in eliminating off-tracking for articulated buses.]]></description>
      <pubDate>Wed, 25 Apr 2007 13:46:40 GMT</pubDate>
      <guid>https://trid.trb.org/View/806467</guid>
    </item>
    <item>
      <title>TUNNEL RESPONSE IN MODELED JOINTED ROCK</title>
      <link>https://trid.trb.org/View/270773</link>
      <description><![CDATA[Laboratory-scale intact and jointed rock masses were tested in field and laboratory experiments to investigate tunnel response in high stress environments.  In most of the experiments the tunnels were modelled by a rigid-plastic foam polyurethane with a crush strength of 3.4 mpa (500 psi) and emphasis was placed on jointed rock parameters: joint sets (single set of parallel plane joints versus a double set of orthogonal parallel plane joints), joint plane angle with respect to the direct load direction, and joint spacing.  Other parameters were loading stress, loading direction, and tunnel reinforcement strength. Results show quantitatively the increase in tunnel deformation in jointed compared with intact rocks, double versus single joint sets, and large versus small angle between the joint plane normal and the loading direction. A surprising result was the decreases in tunnel deformation with increases in the number of joints across a tunnel diameter.  The efficacy of scale modelling with laboratory-constructed rock was tested by modelling complex reinforced concrete and steel tunnel reinforcements in jointed rock masses and comparing the results with large scale tunnels previously fielded in highly jointed granite.  Tunnel response was reproduced in surprising detail, including concrete fracture, steel liner bending and fracture, and critical load to produce these responses.  The scale models also allowed sectioning of the jointed rock masses to observe gross sliding along the joints that accompanied tunnel failure.  For the covering abstract of the symposium see IRRD 284392.  (Author/TRRL)]]></description>
      <pubDate>Fri, 27 Aug 2004 21:59:31 GMT</pubDate>
      <guid>https://trid.trb.org/View/270773</guid>
    </item>
    <item>
      <title>INCORPORATING TRUCK CRASH MODELING INTO A METHODOLOGY FOR EVALUATING THE RELATIVE NEED FOR TRUCK ROUTE IMPROVEMENTS</title>
      <link>https://trid.trb.org/View/725522</link>
      <description><![CDATA[In July 1997 a study entitled "Freight Movement and Intermodal Access in Kentucky" was initiated for a two-year period.  A methodology for evaluation of highway access for trucks along specific truck routes was developed.  In all, 81 routes used for access between 46 facility sites and the National Highway System were evaluated.  These routes represented approximately 800 miles of highway.  The methodology involves tabulation of problem truck miles and problem truck points for the following point and continuous features of the route: lane width, shoulders, railway crossings, grade, safe speed on horizontal curves, offtracking on horizontal curves, intersection turning radii, and stopping sight distance.  Using criteria developed in brainstorming sessions and from reference sources, each of the above features were graded as "preferred", "adequate" or "less than adequate" for truck access. Through use of the problem trucks per day and problem truck miles per day, specific sections or routes can be compared on a feature by feature basis to determine urgency of needed improvements.  However, there is also a need for a measure of the overall route quality in which all features are combined into one weighted route measure.  The objective of this current research project is to use the truck crash histories along the routes where features have already been documented to develop a truck route safety model based on the problem truck points and miles for each feature according to those that correlate to actual crash problems.  The composite measure would be used as a relative urgency measure when different truck routes are being considered for improvements.]]></description>
      <pubDate>Tue, 09 Dec 2003 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/725522</guid>
    </item>
    <item>
      <title>INCREASED CAPACITY AUTOMOBILE TRANSPORTER--FEASIBILITY STUDY AND ROAD-HANDLING ANALYSIS</title>
      <link>https://trid.trb.org/View/712596</link>
      <description><![CDATA[The objective of this project was to study the feasibility of developing automobile transporters with a greater carrying capacity without compromising their handling characteristics. In the context of this project, the primary handling characteristic of interest is offtracking.  The offtracking analysis was based on (1) actual measurements, and (2) computer simulation based on design drawings provided by three equipment manufacturers.  This report presents results from the offtracking analysis performed using the manufacturers designs, as well as alternative designs that were suggested by the University of Michigan Transportation Research Institute.]]></description>
      <pubDate>Fri, 21 Dec 2001 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/712596</guid>
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