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    <title>Transport Research International Documentation (TRID)</title>
    <link>https://trid.trb.org/</link>
    <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>
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      <link>https://trid.trb.org/</link>
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    <item>
      <title>Validation of a Non-Linear Finite Element Vehicle Model Using Multiple Impact Data</title>
      <link>https://trid.trb.org/View/1590854</link>
      <description><![CDATA[A detailed multi-purpose finite element model of a 1994 Chevrolet C-1500 pick-up truck was developed at the FHWA/NHTSA National Crash Analysis Center. The model is the first of its kind developed specifically to address vehicle safety issues, including front and side performance, as well as roadside hardware design. The former application typically involves large regional deformation with impact durations of no more than 150 msec. The latter encompasses damage along a larger portion of the vehicle, and due to longer interaction time between the vehicle and impacted device coupled with the need to observe post impact dynamics, requires simulations that could last as long as 1 second. This paper describes the results of a non-linear finite element computer simulation using this model for frontal full barrier and median highway barrier impacts. These simulations are conducted in support of research studies undergoing at the National Highway Traffic Safety Administration (NHTSA) and the Federal Highway Administration (FHWA) to investigate vehicle compatibility, new offset barrier tests, and highway/vehicle safety issues. Full scale vehicle crash tests conducted by NHTSA and FHWA are used for evaluation of the performance of the model. Two tests are compared, a frontal impact with a full rigid wall and a corner impact to a 42-inch Vertical Concrete Median. The comparisons between tests and simulations in terms of overall impact deformation, component failure modes, velocity and acceleration at various locations in the vehicle are presented. Modeling issues including element size, connectivity, and slide line interface of different parts are discussed. In addition, some simulation related hardware and software issues are addressed. The results clearly indicate the model to be consistent with the full scale tests. Additional simulations need to be performed to fully evaluate and validate the model.]]></description>
      <pubDate>Mon, 18 Mar 2019 22:10:26 GMT</pubDate>
      <guid>https://trid.trb.org/View/1590854</guid>
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    <item>
      <title>Sliding mode guidance for impact time and angle constraints</title>
      <link>https://trid.trb.org/View/1571208</link>
      <description><![CDATA[This paper proposes a guidance strategy, which caters to both impact angle and impact time terminal constraints. This guidance scheme is based on switching between impact time and impact angle guidance laws. Unlike the existing impact time guidance laws, the proposed guidance strategy takes into account the curvature of the trajectory due to requirement of impact angle. The guidance law is derived using sliding mode control theory with the switching surface based on impact time error. The interceptor first corrects its course to nullify the impact time error and then aims to achieve interception with desired impact angle. In order to reduce transitions between the two guidance laws, a novel hysteresis loop is introduced in the switching conditions. The guidance law is initially designed for stationary targets, and later it is extended to constant velocity targets using the notion of predicted interception point. In order to validate the efficacy of the proposed guidance strategy, simulation results are presented with constant as well as realistic time-varying speed interceptor models for different engagement scenarios against stationary and constant velocity targets. The performance of the guidance law is evaluated under noisy measurements and the presence of system lag and its performance is compared with other existing guidance laws.]]></description>
      <pubDate>Mon, 31 Dec 2018 09:05:02 GMT</pubDate>
      <guid>https://trid.trb.org/View/1571208</guid>
    </item>
    <item>
      <title>Three-dimensional impact angle guidance with coupled engagement dynamics</title>
      <link>https://trid.trb.org/View/1458168</link>
      <description><![CDATA[This paper proposes three-dimensional impact angle control guidance laws based on a sliding mode control technique. Unlike the usual approach of decoupling the engagement dynamics into two mutually orthogonal two-dimensional planes, the guidance laws are derived using coupled engagement dynamics. By using this approach, the control effort required to achieve the objective reduces and the performance of the guidance law is improved. The derivations of guidance laws are done using both conventional as well as nonsingular terminal sliding mode control, which guarantees asymptotic and finite time convergence, respectively, to the desired impact angle. In order to derive the guidance laws, multi-dimensional switching surfaces are used. The stability of the system, with selected switching surfaces, is demonstrated using Lyapunov stability theory. Numerical simulation results are presented to validate the proposed guidance laws for constant speed, as well as a realistic interceptor model with given aerodynamic properties. The simulations show the advantage of using coupled dynamics. The robustness of the proposed guidance laws, with respect to the interceptor’s system lag, is also investigated.]]></description>
      <pubDate>Mon, 27 Mar 2017 09:26:51 GMT</pubDate>
      <guid>https://trid.trb.org/View/1458168</guid>
    </item>
    <item>
      <title>Extended state observer based impact angle constrained guidance law for maneuvering target interception</title>
      <link>https://trid.trb.org/View/1409739</link>
      <description><![CDATA[In this paper, a nonsingular, essentially continuous and finite-time convergent impact angle constrained guidance law for intercepting stationary, constant speed, and maneuvering targets is developed using advanced terminal sliding mode control schemes and extended state observer. In order to achieve the specified intercept angle in finite time without singularity, the nonsingular fast terminal sliding mode control algorithm is employed to construct sliding surface. The fast terminal sliding mode control technique is used to establish the reaching law, so the system trajectory converges quickly from initial state to the switching surface in the whole reaching phase and the proposed guidance law is essentially continuous. Noticing the interception of a maneuvering target, the unknown target acceleration is estimated and compensated using extended state observer. Due to its inherent attribute of singularity-free, continuity, and faster convergence rate, no approximation is necessary in the implementation of the proposed guidance law, so better tracking accuracy of the desired intercept angle in a shorter time with a smoother guidance command can be guaranteed compared with conventional terminal sliding mode guidance law. A large number of numerical simulations are implemented to justify the effectiveness of the proposed guidance law.]]></description>
      <pubDate>Mon, 20 Jun 2016 10:27:19 GMT</pubDate>
      <guid>https://trid.trb.org/View/1409739</guid>
    </item>
    <item>
      <title>Assessment of the impact speed and angle conditions for the EN1317 barrier tests</title>
      <link>https://trid.trb.org/View/1407325</link>
      <description><![CDATA[Roadside safety barriers designs are tested with passenger cars in Europe using standard EN1317 in which the impact angle for normal, high and very high containment level tests is 20°. In comparison to EN1317, the US standard Manual for Assessing Safety Hardware (MASH) has higher impact angles for cars and pickups (25°) and different vehicle masses. Studies in Europe (RISER) and the US have shown values for the 90th percentile impact angle of 30°–34°. Thus, the limited evidence available suggests that the 20° angle applied in EN 1317 may be too low. The first goal of this paper is to use the US National Cooperative Highway Research Program (NCHRP)  database (Project NCHRP 17–22) to assess the distribution of impact angle and collision speed in recent run-off road (ROR) accidents. Second, based on the findings of the statistical analysis and on analysis of impact angles and speeds in the literature, an LS-DYNA finite element (FE) analysis was carried out to evaluate the normal containment level of concrete barriers in non-standard collisions. The FE model was validated against a crash test of a portable concrete barrier carried out at the UK Transport Research Laboratory (TRL). The accident data analysis for run-off road accidents indicates that a substantial proportion of accidents have an impact angle in excess of 20°. The baseline LS-DYNA model showed good comparison with experimental acceleration severity index (ASI) data and the parametric analysis indicates a very significant influence of impact angle on ASI. Accordingly, a review of European run-off road accidents and the configuration of EN 1317 should be performed.]]></description>
      <pubDate>Fri, 20 May 2016 15:47:02 GMT</pubDate>
      <guid>https://trid.trb.org/View/1407325</guid>
    </item>
    <item>
      <title>Bank-to-Turn Guidance Law with Terminal Impact-Angle Constraint</title>
      <link>https://trid.trb.org/View/1371840</link>
      <description><![CDATA[To avoid the mathematical singularity of polar converting in bank-to-turn (BTT) guidance and to provide the specified terminal impact angle, a BTT guidance law with impact-angle constraint (BTT-GL/IA) is presented. Considering the influence of the impact-angle control and target maneuver to the miss-distance, a new form zero-effort miss-distance with impact angle (ZEM/IA) is introduced. Referring to the Lyapunov-like approach used to drive the guidance law in the prior literature, a Lyapunov function is constructed in terms of ZEM/IA. Based on the Lyapunov stability theorem, a negative definite function is designed, and the BTT-GL/IA is derived. Next, BTT-GL/IA is implemented in another form with the variables as the line-of-sight angle and its rate, which are easily measured by the seeker. When using BTT-GL/IA, the guidance law tends to maintain smooth and continuously-varied body acceleration and roll-angle commands while satisfying the impact position and angle constraints. The problem of a mathematical singularity in normal BTT polar converting logic is avoided. Finally, both the maneuverable and stationary targets with different impact-angle constraints are considered in numerical simulations. Through various simulation results, the effectiveness and practicality of the BTT-GL/IA are demonstrated.]]></description>
      <pubDate>Mon, 30 Nov 2015 08:29:50 GMT</pubDate>
      <guid>https://trid.trb.org/View/1371840</guid>
    </item>
    <item>
      <title>A biased proportional navigation guidance law with large impact angle constraint and the time-to-go estimation</title>
      <link>https://trid.trb.org/View/1315481</link>
      <description><![CDATA[For large impact angle control problem (here, the “large impact angle” means the impact angle in the closed interval from -180° to 180°), estimating the time-to-go accurately is the key of impact time and impact angle control guidance (ITIACG). The objectives of this paper are to construct a new impact angle control guidance (IACG) law suitable for large impact angle control and present a time-to-go estimation procedure for the new IACG law suitable for designing ITIACG law. The constructed IACG law is a biased proportional navigation guidance law with large impact angle constraint, the rule of the cosine of the lead angle in the biased term is to guarantee that the lead angle remains in the open interval from -90° to 90°, which is required in the development of time-to-go estimation procedure. To estimate the time-to-go, by introducing a self-convergent angle named as alfa, the closed equations of motion are transformed to a different form, which can be solved conveniently under the assumption of small lead angle. For the case of large lead angle, the time interval of time-to-go is partitioned into n segments, the maximum increment of lead angle is supposed to be a small angle in each segment, the transformed closed equations of motion can be expressed as function of alfa angle and solved analytically. A geometric approach is proposed to determine conservatively a suitable alfa angle to guarantee that the maximum increment of lead angle is a small angle in each segment. The time-to-go estimation procedure for the new IACG law are illustrated. Simulations are performed to verify the effectiveness of the proposed IACG law and the accuracy of the time-to-go estimation procedure.]]></description>
      <pubDate>Thu, 31 Jul 2014 09:15:16 GMT</pubDate>
      <guid>https://trid.trb.org/View/1315481</guid>
    </item>
    <item>
      <title>Head Impact Mechanisms of a Child Occupant Seated in a Child Restraint System as Determined by Impact Testing</title>
      <link>https://trid.trb.org/View/1140738</link>
      <description><![CDATA[A sport utility vehicle (SUV)-to-car oblique side crash test was conducted to determine the injury mechanism of a child in a child restraint system (CRS) whose head makes contact with the vehicle interior.  A Q3s child dummy was seated in a CRS in the rear seat of the target car.  The Q3s child dummy's head moved out beyond the CRS side wing, moved laterally, and made contact with the side window glass and the doorsill.  It was demonstrated that the hard head contact, which produced a high Head Injury Criterion (HIC) value, could occur in side collisions.  Sled tests were carried out to reproduce the dummy kinematic behavior observed in the SUV-to-car crash test, and the sled test conditions that duplicated the kinematic behavior were determined.  A parametric study was also conducted with the sled tests, in which it was found that the impact angle, harness slack, chest clip, and the CRS side wing shape affected the torso motion and head contact with the vehicle interior.]]></description>
      <pubDate>Fri, 08 Jun 2012 12:33:26 GMT</pubDate>
      <guid>https://trid.trb.org/View/1140738</guid>
    </item>
    <item>
      <title>MASH Test 3-11 of the TxDOT Single Slope Bridge Rail (Type SSTR) on Pan-Formed Bridge Deck</title>
      <link>https://trid.trb.org/View/1102397</link>
      <description><![CDATA[The objective of this crash test was to determine whether the Texas Department of Transportation (TxDOT) Single Slope Traffic Rail (Type SSTR) would perform acceptably on a pan-formed deck when tested according to the guidelines set forth in the AASHTO Manual for Assessing Safety Hardware (MASH). The crash test performed was MASH test 3-11 involving a 2270P vehicle (5000-lb pickup truck) impacting the critical impact point (CIP) of the bridge rail at an impact speed and angle of 62 mi/h and 25 degrees, respectively. This report presents the details of the TxDOT Type SSTR on pan-formed bridge deck, description of the crash test performed, an assessment of the test results, and the implementation plan. The TxDOT Type SSTR bridge rail on pan-formed deck performed acceptably for MASH test 3-11.]]></description>
      <pubDate>Thu, 12 May 2011 16:31:44 GMT</pubDate>
      <guid>https://trid.trb.org/View/1102397</guid>
    </item>
    <item>
      <title>Median Barrier Placement on Six-lane, 46-foot Median Divided Freeways</title>
      <link>https://trid.trb.org/View/1098768</link>
      <description><![CDATA[This report summarizes the research efforts of using finite element modeling and simulations to evaluate the performance of W-beam guardrails and cable median barriers on six-lane, 46-foot median divided freeways. A literature review is included on performance evaluation of W-beam guardrails and cable barriers as well as applications of finite element modeling and simulations in roadside safety research. The three types of barriers evaluated in this project are the single-face W-beam, double-face W-beam (two designs), and generic low-tension cable barrier. All three types of barriers were evaluated at three impact speeds and three impact angles. Full-scale crash simulations were first performed on a single-face W-beam guardrail placed on the border of a 2.5:1 slope and the shoulder. Two designs of a double-face W-beam guardrail, which replaced the single-face W-beam at the same location, were then evaluated using simulations and compared to the single-face one. Finally, simulations were performed on vehicles impacting the cable median barrier placed on a 4:1 slope. The simulation results demonstrated the effects of sloped medians on vehicle redirection after contacting the cable median barriers or W-beam guardrails. A common issue for a sloped median is the increased potential of vehicle rollovers, particularly for large-size vehicles. The results will be used to update and validate the standard drawings and strategies for placement of median guardrails and cable barriers. The use of finite element simulations is shown to be both effective and efficient, because they are nondestructive, repeatable, modifiable, and inexpensive. Furthermore, finite element simulations can be used to study crash scenarios that are impossible and/or extremely expensive to conduct physical crash testing. Finite element modeling and simulations are recommended for future investigations of other research issues.]]></description>
      <pubDate>Wed, 06 Apr 2011 16:31:17 GMT</pubDate>
      <guid>https://trid.trb.org/View/1098768</guid>
    </item>
    <item>
      <title>Zone of Intrusion Study</title>
      <link>https://trid.trb.org/View/1082561</link>
      <description><![CDATA[The Midwest Roadside Safety Facility (MwRSF) performed an analysis using LS-DYNA simulation to investigate the zone of intrusion (ZOI) of an NCHRP Report No. 350 2000-lb pickup truck when impacting a 40-in. high F-shape parapet. The ZOI for the 40-in. F-shape concrete barrier impacted by the 2000-lb vehicle at 62 mph at an angle of 25 degrees (equivalent to TL-3) is predicted to be 5 in. The ZOI for the 40-in. F-shape concrete barrier impacted by the 2000-lb vehicle at 45 mph at an angle of 25 degrees (equivalent to TL-2) is predicted to be between 1.8 and 2.5 in., depending on the impact conditions simulated. The variations in this relatively small ZOI are attributed to the mesh quality of the model and to the system geometry. The 2000-lb pickup truck front hood geometry is such that it will extend over a 40-in. high F-shape parapet during impact conditions examined in this study. Thus, some ZOI is inevitable at almost all impact speeds. However, compared to a 32-in. parapet, the amount of structure extending over the 40-in. barrier is possibly inconsequential. That is, with a 32-in. parapet a significant amount of vehicle structure will overhang the barrier and potentially cause problems within the ZOI. With the 40-in. parapet, the amount of vehicle structure overhanging the barrier is limited to the front corner of the hood and possibly a little bit of the fender. This limited amount of structure in the ZOI may not cause any problems during an impact event.]]></description>
      <pubDate>Mon, 29 Nov 2010 12:04:15 GMT</pubDate>
      <guid>https://trid.trb.org/View/1082561</guid>
    </item>
    <item>
      <title>Evaluation of Barriers for Very High Speed Roadways</title>
      <link>https://trid.trb.org/View/916328</link>
      <description><![CDATA[As the Texas Department of Transportation (TxDOT) plans for future expansion of the state’s highway network, interest in higher design speeds has been expressed as a means of promoting faster and more efficient travel and movement of goods within the state. TxDOT funded project 0-6071 as part of a proactive consideration of safety on these high-speed facilities. This project began the process of developing roadside safety hardware suitable for use on high-speed highways. The impact conditions selected for the design, testing, and evaluation of this high-speed hardware include a speed of 85 mi/h and an angle of 25 degrees for barrier impacts. The design vehicles are those specified by the pending AASHTO Manual for Assessing Safety Hardware (MASH) and include a 5000-lb, ½-ton, 4-door pickup truck and a 2425-lb passenger car. After consideration of several barrier systems, two designs were selected for further evaluation through full-scale crash testing. These included an energy absorbing bridge rail concept and a modified wood post thrie beam guardrail. The results of the full-scale crash testing are presented and recommendations for future research are discussed.]]></description>
      <pubDate>Thu, 29 Apr 2010 16:32:25 GMT</pubDate>
      <guid>https://trid.trb.org/View/916328</guid>
    </item>
    <item>
      <title>Roadway Departure and Impact Conditions</title>
      <link>https://trid.trb.org/View/910742</link>
      <description><![CDATA[In-depth accident data were collected to investigate vehicle impact conditions (e.g., crash severity, impact speed, impact angle, and orientation) for crashes with roadside obstacles and features. Descriptive statistics of these variables are presented, including statistics for the data segregated by highway class, speed limit, and access control. Relationships between impact conditions and these segregating factors were explored. Statistical tests were applied to investigate the association between speed and angle, and univariate distributions were fitted for these two variables. Impact speed and impact angle are independent for most highway classes when segregated by highway class, and they have a relatively weak negative correlation. Both impact speed and angle data for all highway classes follow a normal distribution. Joint impact distributions were then determined using the bivariate normal distribution. The findings of this study are of significant importance to the establishment or reinforcement of full-scale vehicle crash testing guidelines, to benefit–cost analysis procedures, and to highway designers who seek more detailed information on probabilities of impact conditions for different highway classes.]]></description>
      <pubDate>Mon, 22 Feb 2010 10:28:47 GMT</pubDate>
      <guid>https://trid.trb.org/View/910742</guid>
    </item>
    <item>
      <title>New Test Level 2 Rough Stone Masonry Guardwall</title>
      <link>https://trid.trb.org/View/909308</link>
      <description><![CDATA[A minimum mounting-height rough stone masonry guardwall was designed and successfully crash tested to meet Test Level 2 (TL-2) safety performance criteria found in NCHRP Report 350. Several design concepts were considered for providing shear transfer between the top capstones and the inner core wall. The new design uses steel angle segments anchored to the core wall with the upper leg recessed into saw-cuts placed in the capstones. LS-DYNA simulations were performed with varying barrier heights to evaluate the propensity for vehicular instabilities and barrier override. Two crash tests were performed. The first test was performed on a 22-in.-tall guardwall with a 2000P pickup truck impacting at a speed of 44.4 mph and at an angle of 24.2°. The second test was performed on a 20-in.-tall guardwall with another 2000P vehicle impacting at a speed of 43.6 mph and at an angle of 24.4°. Both crash tests provided acceptable safety performance. Although the 20-in.-tall parapet adequately contained and redirected the pickup truck at the TL-2 conditions, barrier performance was slightly degraded over that observed in the 22-in.-tall parapet. On the basis of the results of this study and for new construction, it is recommended that the rough stone masonry guardwall system be implemented using a nominal top mounting height of 22 in. relative to the traveled way. A significant benefit of this nominal height is that roadways requiring resurfacing could be accommodated using a 2-in. pavement overlay placed adjacent to the barrier system.]]></description>
      <pubDate>Mon, 25 Jan 2010 10:07:23 GMT</pubDate>
      <guid>https://trid.trb.org/View/909308</guid>
    </item>
    <item>
      <title>Rib Cage Strain Pattern as a Function of Chest Loading Configuration</title>
      <link>https://trid.trb.org/View/888013</link>
      <description><![CDATA[The most frequent type of AIS3+ chest injury is rib fracture.  The behavior of the rib cage, however, is not well documented, and though chest external measurements are often provided in the literature, the strains on the ribs themselves during a crash remain unknown.  To address this issue, a test protocol was developed, where the ribs of 8 post-mortem human subjects (PMHS) were equipped with up to 96 strain gages.  In a first series of 3 tests, the subjects were seated upright and their chests were loaded by a 23.4 kg impactor propelled at 4.3 m/s at 0 deg (pure frontal), 60 deg (oblique) and 90 deg (pure lateral) directions.  In a second series of 3 tests, the subjects were loaded by the deployment of an unfolded airbag in the same 3 directions.  Finally, a third series of 2 tests was performed with airbags at different distances from the subjects, in a pure lateral direction.  This paper presents the results of the tests and an analysis of the strain patterns.  Results include (1) the differences between a pure frontal, a pure lateral and an oblique loading; (2) a comparison of airbag loading to impactor loading and the severity effect; and (3) an analysis of the time and location of the rib fractures as a function of the test configuration.]]></description>
      <pubDate>Mon, 04 May 2009 10:43:51 GMT</pubDate>
      <guid>https://trid.trb.org/View/888013</guid>
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