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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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    <language>en-us</language>
    <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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      <link>https://trid.trb.org/</link>
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    <item>
      <title>A Study on the Injury Risk of Occupant with Different Head and Neck Rotating Postures under the Frontal Impact Sled Conditions</title>
      <link>https://trid.trb.org/View/2692054</link>
      <description><![CDATA[Drivers obtain road information through head and neck rotation. In order to study the influences of head and neck rotation posture on occupant injury in frontal impact scenario, the THUMS (Total Human Model for Safety) AM50 human body model with five different head and neck rotation postures but without active muscles was adopted to study the biomechanical injury responses of occupant under the frontal impact scenario at 56 km/h in this study. Firstly, the kinematic responses of total body and head acceleration curves at the center of gravity predicted by PMHS (Post Mortem Human Subject) and THUMS AM50 human model under the sled test conditions were compared to verify the simulation model for subsequent study. Then, the THUMS AM50 human model with standard occupant seating posture was adjusted to have five different head and neck rotation postures with 0°, ±20°, and ±40° rotation angle, respectively. Finally, a series of frontal impact sled with or without airbag simulations were conducted for each THUMS AM50 human model with different head and neck rotation postures. The simulation results showed that with the increasing of head and neck rotation angle, the neck injury risk was increased while the thoracic injury risk was decreased. Regardless of whether airbags were present or absent, the model prediction for the standard posture indicated a lower injury risk. And regardless of whether the head and neck posture changed, the airbag always could provide a certain protection in that posture.]]></description>
      <pubDate>Tue, 14 Apr 2026 15:11:23 GMT</pubDate>
      <guid>https://trid.trb.org/View/2692054</guid>
    </item>
    <item>
      <title>The effect of time-extended evasive swerving maneuvers on occupants’ bracing strategies</title>
      <link>https://trid.trb.org/View/2617060</link>
      <description><![CDATA[Occupant bracing behavior in pre-crash maneuvers has been previously investigated but the effect of the duration of the pre-crash maneuver on bracing is unknown. This is critical to understand as time-extended pre-crash maneuvers may emerge in cases where drivers lose control of a vehicle and in autonomous vehicles as they may take different approaches to avoid crashes than the current vehicles. Therefore, the aim of this study was to understand the effect of pre-crash maneuver duration on child and adult occupants’ bracing behavior and resulting kinematics. Forty seatbelt restrained subjects (9–40 years old) experienced sled-simulated time-extended lateral swerving maneuvers (8 s, 4 cycles, peak acceleration 0.7 g) producing an alternating motion initially out-of-the-belt, followed by into-the-belt for each cycle. In a braced condition, subjects were instructed to hold on to a laterally placed handle with their right hand before the maneuver onset, while in an unbraced condition no instructions were given. A 3D-motion capture system, electromyography (EMG), and seatbelt load cells captured head and trunk kinematics (normalized to seated height), muscle activation (normalized to maximum voluntary isometric contraction, MVIC), and seatbelt reaction forces (normalized to body weight), respectively. The effects of cycles and interaction with bracing and age on peak lateral head and trunk displacement into- and out-of-the belt were examined with Mixed-Effects Models and Tukey’s post-hoc tests (p ≤ 0.05). Out-of-the-belt peak lateral head and trunk displacements were the greatest in the first cycle and the smallest in the second cycle (p<0.01). The third and four cycles were not significantly different from one another (p>0.8). Into-the-belt peak lateral head and trunk displacements were smaller in the first cycle than the remaining cycles (p<0.001) and were not significantly different across the remaining cycles (p>0.8). No interactions between cycle, age and bracing were found (p>0.3). Right bicep, trapezius and rectus femoris activations slightly increased with increasing cycles in the unbraced condition and in the into-the-belt direction for the 9–11 year-old group. Out-of-belt seat belt loads increased with increasing cycles in the unbraced condition for all age groups. Occupant kinematics as a result of their bracing behavior changed across cycles of swerving maneuvers from an exaggerated displacement in cycle 1 to an overcompensation due to bracing in cycle 2, ending with a plateau of a moderate displacement in cycle 3 and 4. Younger children (age 9–11) took longer to adapt to the oscillatory motion as they increased their muscle activation over time unlike the other age groups. These findings suggest that it may take time for occupants to find the optimal bracing strategy in time-extended maneuvers. Furthermore, children may find challenging to calibrate their bracing response overtime from a neuromotor perspective.]]></description>
      <pubDate>Wed, 19 Nov 2025 17:09:39 GMT</pubDate>
      <guid>https://trid.trb.org/View/2617060</guid>
    </item>
    <item>
      <title>Overview of Seat Design Changes and Performance</title>
      <link>https://trid.trb.org/View/2539661</link>
      <description><![CDATA[The National Highway Traffic Safety Administration (NHTSA) published an Advance Notice of Proposed Rulemaking (ANPRM) to update the Federal Motor Vehicle Safety Standard (FMVSS) 207. Part of the ANPRM is to assess the merit of conducting quasi static body block seat pull tests and conducting FMVSS 301 rear crash tests at 80 km/h or higher with a 95th percentile ATD lap-shoulder belted in the front seats and limiting seatback deflection to 15 to 25 degrees. Prior to updating regulations, it is important to understand the seating design history and implications.This study was conducted to provide a historical background on seat design and performance using literature and test data. One objective was to first define the terminology used to describe occupant kinematics in rear crashes. Secondly, seat design evolution is then discussed. Third, test methods and test results were summarized, and fourth, the field performance are synopsized and discussed with respect to 2nd row occupant protection.Seat design evolution: Seat designs have continuously evolved for the last 70 years, including changes in seat structure and seat/head restraint geometry. Over the past decades, seatbacks have become taller and include open perimeter frames and dual recliners. Head restraints have become larger and/or more forward. Seat properties have also changed over time, resulting in better performance. These changes resulted in an increase in strength. The changes in design and properties allow the occupant to pocket while offering load-limiting and controlled head and neck support.Test method summary: Various methods are used to evaluate seat performance, including quasi-static pull tests and dynamic sled tests. Pull tests include applying a rearward load at the upper cross member of the seatback frame, which does not account for the interaction between the occupant and the seat. Other test methods include using a body block as suggested in the ANPRM. Many tests have been conducted with the body block representative of the upper torso geometry and center of gravity (cg) of a 50th percentile occupant. The data show a continuous increase in rearward loading strength, averaging 1,232 Nm (10,902 in-lbs) in seats with model year (MY) 1989 and older and 3,244 Nm (28,716 in-lbs) in MY 2010+, decreasing dynamic seatback rotation. FRED (Ford Rear-Impact Energy Device) is another type of device used in pull testing. FRED provides a more biofidelic test for occupant loading and interaction with the seat; the load location coincides with the cg of a 50th percentile occupant. However, there is less FRED data available for historical comparisons.Sled tests are conducted at low-to-moderate speeds and at high-speed. For example, low-to-moderate speed sled tests are conducted at 16 km/h as part of the Insurance Institute Highway Safety (IIHS) head restraint evaluation program, terminated in 2022, and at 17.3 km/h as part of FMVSS 202a.Testing and field performance: The result of this study suggests that the newer seat designs are performing well. Modern seats (2010+ MY) exceed the FMVSS 207 static strength requirement by a factor greater than 8 on average. Dynamic sled tests, conducted with the BioRID and with the 50th Hybrid III, show good performance. The occupant biomechanical responses obtained from 40 km/h rear sled tests remain well below injury thresholds. There was a decrease in neck extension. Chest g’s 3ms however remined similar irrespective of MY group; it averaged 14.6 ± 4.6g with 1990-1999 MY- and 15.7 ± 2.4g in 2010+ MY seats. In either the earlier or more recent MY vehicles, these peak chest accelerations occurred prior to maximum seatback deflection.Conclusion: These results of this study provide background for consideration of future test requirements. Overall, conducting dynamic sled tests with a FMVSS 301R impact energy and 50th percentile male ATD may be valuable. However, selecting a maximum dynamic deflection limit would require additional work, as it may affect seat yielding performance. Yielding is beneficial for overall crash safety, particularly for older and/or more vulnerable occupants. Protecting rear seat occupants from front seat interaction may be the reasoning behind limiting the seatback deflection. Care must be taken in understanding the cause of injury risk to rear occupants when considering design changes that may influence the risk to front seat occupants, especially since the front seats are occupied at a higher rate than rear seats. For example, the literature review indicates that factors outside of front seat design such as intrusion were a significant factor on second-row occupant injury outcomes.The size of the BioRID and 50th Hybrid III used in sled testing is representative of an average driver involved in tow-away crashes. Conducting tests with 95th percentile ATD may thus bias the data and could have unintended consequences for smaller or vulnerable occupants.]]></description>
      <pubDate>Tue, 15 Apr 2025 13:56:52 GMT</pubDate>
      <guid>https://trid.trb.org/View/2539661</guid>
    </item>
    <item>
      <title>An evaluation of front seat distance from rear facing child restraint systems in prevention of injury in frontal crash tests</title>
      <link>https://trid.trb.org/View/2507287</link>
      <description><![CDATA[Elevated head injury incidence in infants compared to toddlers involved as occupants in motor vehicle crashes has been demonstrated in multiple population-representative crash databases. Further, experimental studies have revealed a potential injury mechanism via impact between a rear-facing, CRS-restrained child and the back of the vehicle seat or console on the row in front of the CRS. Subsequently, experimental studies have suggested that bracing the CRS against the seat immediately in front of the CRS could mitigate head injury, but also indicated that more research was necessary. Thus, the authors investigated the effect of bracing against the front seat, as well as distance from the front seat with rear-facing infant carriers and rear-facing convertibles, with a focus on changes to measured head, neck and chest injury metrics in rear facing CRSs. Further, the authors examined the effect of using the infant carrier with and without a base on these injury metrics. 34 frontal sled tests at 30 or 35 mph were conducted using a simulated rear-row vehicle seat and structure representing the front seatback. A Q1.5 anthropomorphic test device (ATD) was placed in a single make/model LATCH-affixed rear-facing convertible or single make/model infant carrier; infant carrier without base was affixed with lap and shoulder belt. To evaluate the effect of bracing and distance, tests were conducted with a 300, 140, 70, or 15 mm gap between the CRS seatback and the front seatback, or a touching (0 mm) or braced (-20 mm) condition. Bayesian regression models quantified the effects of various predictors and model uncertainty. For tests with the convertible CRS, no head contact was observed between the head and the front vehicle seatback. For the infant carrier, head contact occurred at both 70 and 140 mm distances but not the other distances. On average, the −20, 0, or 15 mm distances yielded a 60% reduction in head injury criterion with 15 millisecond window (HIC15), and a 60% to 80% reduction in neck tension, compared to the 70 and 140 mm distances; chest acceleration also decreased for the convertible seat only. In the case of both carriers and convertibles, each mm of distance the CRS moves away from the front seatback up to 70 mm, adds 5.3 HIC15 points (95% Credible Interval (CrI):[4.6, 6.2]), and 3.5 Newtons (95% CrI: [2.2, 4.8]) of neck tension, on average. Placing a rear facing CRS, both convertibles and infant carriers, against or close to the seatback of the seat immediately in front of the CRS reduces head and tensile neck injury criteria in ATDs. The amount of gap between the front seat and the rear facing CRS is strongly and positively correlated with HIC for both convertibles and infant carriers. RF infant carriers with and without a base yield comparable injury metrics and kinematics when touching or nearly touching the back of the front vehicle seatback.]]></description>
      <pubDate>Tue, 18 Mar 2025 15:48:12 GMT</pubDate>
      <guid>https://trid.trb.org/View/2507287</guid>
    </item>
    <item>
      <title>The Effect of Crash Pulse Shape on Occupant Simulations</title>
      <link>https://trid.trb.org/View/1787497</link>
      <description><![CDATA[Computer simulations are frequently used to analyze occupant kinematics in motor vehicle crashes, including what they collide with during the crash and the severity of these internal collisions. From study of such occupant simulations, it is then possible to infer how the actual human occupants may have been injured in a crash. When using a simulation to study how occupants react in a vehicle crash, a crash-pulse is usually required as input to the occupant simulation model. This crash-pulse is typically generated from a study of the vehicle motion and acceleration during the crash. There are several different methods for obtaining such a crash-pulse which are in common use. Each of these methods produces a different shape for the crash-pulse, even with identical velocity changes for the vehicle. The time duration, maximum acceleration, and general shape of the crash-pulse may influence the predicted motion of the occupants. In this research, the GATB (Graphical Articulated Total Body) computer simulation model is used to study basic occupant kinematics using a variety of shapes for the crash-pulse, in order to determine how the specific shape of the crash-pulse affects the predicted occupant kinematics.]]></description>
      <pubDate>Wed, 22 Jan 2025 09:33:56 GMT</pubDate>
      <guid>https://trid.trb.org/View/1787497</guid>
    </item>
    <item>
      <title>Summary of Poster Abstracts</title>
      <link>https://trid.trb.org/View/2483093</link>
      <description><![CDATA[Seventeen research posters were prepared and presented by student authors. The                     posters covered a wide breadth of works-in-progress and recently completed                     projects. Topics included a variety of body regions and injury scenarios:                                                      Biofidelity Corridors of Powered Two-Wheeler Rider Kinematics from                                 Full-Scale Crash Testing Using Postmortem Human Subjects, Meringolo                                 et al.                                                                               Cervical Vertebral and Spinal Cord Injuries Remain Overrepresented in                                 Rollover Occupants, Al-Salehi et al.                                                                               The Effect of Surfaces on Knee Biomechanics during a 90-Degree Cut,                                 Rhodes et al.                                                                               Investigating the Variabilities in the Spinal Cord Injury in Pig                                 Models Using Benchtop Test Model and Ultrasound Analyses, Borjali et                                 al.                                                                               Relationship between Tackle Form and Head Kinematics in Youth                                 Football, Holcomb et al.                                                                               Comparing Motor Vehicle Collision Injury Incidence between Pregnant                                 and Nonpregnant Individuals: A Case–Control Study, Levine et al.                                                                               Development of an Automated Pipeline to Characterize Full Rib Cage                                 Shape Variability, Robinson et al.                                                                               Soft Tissue Force Attenuation and Redistribution during Lateral Hip                                 Impacts, Pretty et al.                                                                               Hybrid III Small Female Neck Interaction with a Driver Airbag:                                 Preliminary Observations, Boyle et al.                                                                               Changes in Youth Football Athletes’ Oculomotor Task Metrics across                                 Three High School Seasons of Play, Pang et al.                                                                               Measurement of Shielding Stiffness in Ice Hockey, Vakili et al.                                                                               Investigating the Relationship between Vehicle-Based and Biomechanics                                 Injury Metrics in Car-to-End Terminal Crashes Using a Human Finite                                 Element Model, Buckland et al.                                                                               On-Field Instrumented Mouthguard Coupling, Luke et al.                                                                               Investigation of Rear-Seat Occupant Safety during High-Speed Frontal                                 Crashes Using GHBMC M50-O, Dahiya et al.                                                                               Deformable Headform Design Choices: An Evaluation of Brain Simulant                                 Stiffness Influence on Intracranial Displacements and Strain, Xu et                                 al.                                                                               Changes in Neurocognitive Outcomes among Youth Football Teams                                 Participating in an Intervention, Marks et al.                                                                               A Parametric Skeleton Model of Human Upper Extremities Accounting for                                 Morphological Variations among the Diverse Population, Neeluru et                                 al.]]></description>
      <pubDate>Mon, 30 Dec 2024 11:54:24 GMT</pubDate>
      <guid>https://trid.trb.org/View/2483093</guid>
    </item>
    <item>
      <title>Computational interaction models for automated vehicles and cyclists</title>
      <link>https://trid.trb.org/View/2389005</link>
      <description><![CDATA[Cyclists' safety is crucial for a sustainable transport system. Cyclists are considered vulnerable road users because they are not protected by a physical compartment around them. In recent years, passenger car occupants' share of fatalities has been decreasing, but that of cyclists has actually increased. Most of the conflicts between cyclists and motorized vehicles occur at crossings where they cross each other's path. Automated vehicles (AVs) are being developed to increase traffic safety and reduce human errors in driving tasks, including when they encounter cyclists at intersections. AVs use behavioral models to predict other road user's behaviors and then plan their path accordingly. Thus, there is a need to investigate how cyclists interact and communicate with motorized vehicles at conflicting scenarios like unsignalized intersections. This understanding will be used to develop accurate computational models of cyclists' behavior when they interact with motorized vehicles in conflict scenarios. The overall goal of this thesis is to investigate how cyclists communicate and interact with motorized vehicles in the specific conflict scenario of an unsignalized intersection. In the first of two studies, naturalistic data was used to model the cyclists' decision whether to yield to a passenger car at an unsignalized intersection. Interaction events were extracted from the trajectory dataset, and cyclists' behavioral cues were added from the sensory data. Both cyclists' kinematics and visual cues were found to be significant in predicting who crossed the intersection first. The second study used a cycling simulator to acquire in-depth knowledge about cyclists' behavioral patterns as they interacted with an approaching vehicle at the unsignalized intersection. Two independent variables were manipulated across the trials: difference in time to arrival at the intersection (DTA) and visibility condition (field of view distance). Results from the mixed effect logistic model showed that only DTA affected the cyclist's decision to cross before the vehicle. However, increasing the visibility at the intersection reduced the severity of the cyclists' braking profiles. Both studies contributed to the development of computational models of cyclist behavior that may be used to support safe automated driving. Future work aims to find differences in cyclists' interactions with different vehicle types, such as passenger cars, taxis, and trucks. In addition, the interaction process may also be evaluated from the driver's perspective by using a driving simulator instead of a riding simulator. This setup would allow us to investigate how drivers respond to cyclists at the same intersection. The resulting data will contribute to the development of accurate predictive models for AVs.]]></description>
      <pubDate>Mon, 10 Jun 2024 14:05:15 GMT</pubDate>
      <guid>https://trid.trb.org/View/2389005</guid>
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    <item>
      <title>Occupant Kinematics During Chain-Collisions: Discrete vs Combined Collisions</title>
      <link>https://trid.trb.org/View/2367509</link>
      <description><![CDATA[There is little prior research into chain-collisions, despite their relatively large contribution to injury and harm in motor-vehicle collisions. This study conducted a series of rear-impact, front-impact, and chain-collision impacts using a bumper car ride at an active amusement park as a proxy for automobiles. The purpose was to begin to identify the threshold time range when separate, discrete collisions transition into a hybrid or combined chain-collision mode and provide bases for future analyses. The test series consisted of rear impacts into an occupied target vehicle from a driven bullet vehicle; frontal impacts into a perimeter barrier (wall); chain-collisions consisting of a driven bullet vehicle striking an occupied primary target vehicle, which then collided with a non-occupied secondary target vehicle; and chain-collisions consisting of a driven bullet vehicle striking an occupied primary target vehicle which then collided with a wall. Time between collisions was adjusted via spacing. Vehicle impact velocities, changes in velocity (delta-Vs), accelerations, and coefficients of restitution are reported. Head and extremity excursions of the restrained occupant of the primary target vehicle were also tracked using high-speed video recording. The results show that chain-collisions exhibited three phases: an early phase that occurs during the initial rearward occupant excursion, a middle phase that occurs during the forward rebound occupant excursion, and a late phase that occurs while the occupant is recovering back to the initial position. The first phase appears to last for approximately 150 ms, the middle phase for approximately 50 to 75 ms, and the late phase from thereafter until approximately 400 ms to 500 ms after the initial collision. The middle phase appears to be related to the timing of the occupant’s return to their original position and their maximum rebound velocity and the late phase to the remaining occupant displacement but not velocity. Overall, occupant and vehicle kinematics during a chain-collision were different from those of the individual component collisions and were different from a superposition of the component collisions. This is the first reporting of these phases in a chain-collision.]]></description>
      <pubDate>Tue, 16 Apr 2024 09:52:53 GMT</pubDate>
      <guid>https://trid.trb.org/View/2367509</guid>
    </item>
    <item>
      <title>Summary of Poster Abstracts</title>
      <link>https://trid.trb.org/View/2341879</link>
      <description><![CDATA[Eighteen research posters were prepared and presented by student authors at the                     18th Annual Injury Biomechanics Symposium. The posters covered a wide breadth of                     works-in-progress and recently completed projects. Topics included a variety of                     body regions and injury scenarios such as:Head: Defining the mass, center of                                 mass, and anatomical coordinate system of the pig head and brain;                                 the influence of friction on oblique helmet testing; validation of                                 an in-ear sensor for measuring head impact exposure in American                                 footballNeck and spine:                                 Design of paramedic mannequin neck informed by adult passive neck                                 stiffness and range of motion data; identifying injury from                                 flexion-compression loading of porcine lumbar intervertebral                                 discThorax: Tensile                                 material properties of costal cartilage perichondrium; finite                                 element models of both an ovine thorax and adipose tissue for                                 high-rate non-penetrating blunt                                     impactPelvis:                                 Injurious pelvis deformation in high-speed rear-facing frontal                                 impactsLower extremities:                                 Generation of 3D pediatric femur models from 2D radiographs; plantar                                 thickness and stiffness using ultrasound; knee injuries in skiing                                 and snowboarding using artificial intelligence 3D modeling; jumping                                 kinematics, and kinetics in athletes with secondary task of heading                                 a soccer ballFull body, vehicle                                     occupants: Comparison of Hybrid III, THOR mid-size male,                                 and small female ATDs in frontal sled tests; effects of booster seat                                 on reclined small females during lateral oblique low-acceleration                                 impacts; airbag deployment for out-of-position 50th percentile male                                 human body modelFull body,                                     unique loading scenarios: Development of seat fixture and                                 restraints for FE human body model during vertical loading;                                 methodology for PMHS-occupied powered two wheeler and motor vehicle                                 crash scenario]]></description>
      <pubDate>Tue, 20 Feb 2024 10:03:38 GMT</pubDate>
      <guid>https://trid.trb.org/View/2341879</guid>
    </item>
    <item>
      <title>Seat Belt Restraint Evidence Generated by Unrestrained Occupant Interaction in a Rollover</title>
      <link>https://trid.trb.org/View/1938081</link>
      <description><![CDATA[Assessment of the physical evidence on a seat belt restraint system provides one source of data for determining an occupant’s seat belt use or non-use during a motor vehicle crash. The evidence typically associated with loading from a restrained occupant has been extensively researched and documented in the literature. However, evidence of loading to the restraint system can also be generated by other means, including the interaction of an unrestrained occupant with a stowed restraint system. The present study evaluates physical evidence on multiple stowed restraint systems generated via interaction with unrestrained occupants during a full-scale dolly rollover crash test of a large multiple passenger van. Unbelted anthropomorphic test devices (ATDs) were positioned in the driver and right front passenger seats and in all designated seating positions in the third, fourth, and fifth rows. Occupant kinematics during the dolly rollover were evaluated through on-board and off-board real-time and high-speed video, and physical evidence on the restraint systems was documented. Analysis of the occupant kinematics demonstrated multiple ATD interactions with stowed restraint systems in the vehicle, which generated corresponding physical evidence on those restraint systems. The findings of the present study demonstrate that the presence of physical evidence on the restraint system alone is insufficient for determination of occupant seat belt usage. A methodology for assessing restraint webbing and hardware evidence in the context of occupant seat belt use versus non-use is detailed. Thorough documentation of the restraint system physical evidence, evaluation of the occupant kinematics and injury patterns, and evaluation of the restraint system evidence as it relates to the body habitus of the occupant of interest can provide an objective scientific basis for the determination of occupant restraint status.]]></description>
      <pubDate>Wed, 06 Apr 2022 14:18:19 GMT</pubDate>
      <guid>https://trid.trb.org/View/1938081</guid>
    </item>
    <item>
      <title>Research of Occupant kinematics and Injury values of Hybrid III, THOR, and human FE model in Oblique Frontal Impact</title>
      <link>https://trid.trb.org/View/1834999</link>
      <description><![CDATA[This paper describes impact kinematics and injury values of Hybrid III AM50, THOR AM50 and THUMS AM50 in simulated oblique frontal impact conditions. A comparison was made among them in driver and passenger seat positions of a midsize sedan car finite element (FE) model. The simulation results indicated that the impact kinematics of THOR was close to that of THUMS compared to that of the Hybrid III. Both THOR and THUMS showed z-axis rotation of the rib cage, while Hybrid III did not. It was considered that the rib cage rotation was due primarily to the oblique impact but was allowed by flexibility of the lumbar spine in THOR and THUMS. Lateral head displacement observed in both THOR and THUMS was mostly induced by that rotation in both driver seat and passenger seat positions. The BrIC, thorax and abdominal injury values were close to each other between THOR and THUMS, while HIC15 and Acetabulum force values were different. The high BrIC values in THOR and THUMS were consistent with the filed data showing a high frequency of driver head injury in oblique frontal collisions. Thus, the simulation results suggested that THOR well simulated the impact kinematics and injury values of THUMS in the oblique frontal impact condition.]]></description>
      <pubDate>Thu, 09 Dec 2021 10:38:35 GMT</pubDate>
      <guid>https://trid.trb.org/View/1834999</guid>
    </item>
    <item>
      <title>ATD Response in Oblique Crash Tests</title>
      <link>https://trid.trb.org/View/1834981</link>
      <description><![CDATA[Oblique crashes to the vehicle front corner may not be characteristic of either frontal or side impacts. This research evaluated occupant response in oblique crashes for a driver, rear adult passenger, and a rear child passenger. Occupant responses and injury potential were evaluated for seating positions as either a far-or near-side occupant. Two crash tests were conducted with a subcompact car. The vehicle’s longitudinal axis was oriented 45 degrees to the direction of travel on a moving platform and pulled into a wall at 56 km/h. Dummies utilized for the seating positions were an adult dummy (50th-percentile-HIII and THOR-Alpha) for the front-left (driver) position, 5th-percentile-female-HIII for the right-rear position, and a 3-year-old HIII for the left-rear position. Test results indicate the driver is at risk of head injury in both conditions and for the far-side position had potential for thoracic/abdominal injuries as the inflatable restraint was not engaged and the occupant slid out of the shoulder belt. The 3-year-old child occupant experienced high neck tension and its head translated beyond the child restraint’s side wings. The small female dummy approached the acceptable limit for the chest acceleration metric in the far-side rear seating position and exceeded the neck IARV in the near side position. Oblique crashes may challenge the sensing and deployment algorithms of restraint control modules, and the resulting occupant kinematics may present a more challenging scenario for occupant protection systems. Ensuring optimal deployment of restraint systems and optimizing restraint performance for oblique occupant motion would likely improve occupant outcomes in oblique impacts.]]></description>
      <pubDate>Thu, 09 Dec 2021 10:38:35 GMT</pubDate>
      <guid>https://trid.trb.org/View/1834981</guid>
    </item>
    <item>
      <title>A Study to Address the Failure Mechanism of the Conventional 3-Point Restraint in Protecting the Far Side Occupant in a Rollover Accident</title>
      <link>https://trid.trb.org/View/1831723</link>
      <description><![CDATA[Occupant motion in a vehicle rollover accident is a function of many factors. Some important ones are vehicle kinematics, position of the occupant in the vehicle, occupant size, ground topology and restraint usage. The far side belted occupants are more vulnerable than the near side occupants in a rollover accident as they have more energy as a result of their trailing and higher side of the vehicle. This outcome is attributable to the inadequate safety performance of the conventional single loop; B-pillar mounted D-ring restraints. Roof crush tends to displace the vehicle's B-pillar, resulting in D-Ring displacement which causes slack in the lap portion of the restraint. This slack enables centrifugal loads to move the far side occupant further away from the vehicle's instantaneous point of rotation. In this scenario, the presence of any ejection portal can result in an occupant becoming partially or fully ejected.         The coupling technique is used between the Finite Element (FE) LS-DYNA and Multibody-MADYMO code to demonstrate the slack generation in the lap belt during vehicle roof to ground contact. The MADYMO FMVSS 208 driver side rollover simulation is conducted to compare and evaluate seat integrated restraints with the B-pillar mounted D-ring restraints. The head excursion is quantified and used as a response to compare the performance of these two types of restraints. The effectiveness of the buckle pretensioner in a rollover accident is also analyzed by comparing the performance of the restraint with and without the pretensioner.         This study is performed using occupant anthropometry from a real world accident involving a far side belted female occupant who was fully ejected. This study revealed the inadequate performance and failure of the conventional single loop restraint to prevent the far side occupant's excessive head excursion and ejection. This study also demonstrates the superior performance and added advantages of the seat integrated restraint with and without the buckle pretensioner over the B-pillar mounted D-ring restraint.]]></description>
      <pubDate>Thu, 09 Dec 2021 10:37:44 GMT</pubDate>
      <guid>https://trid.trb.org/View/1831723</guid>
    </item>
    <item>
      <title>Fidelity of Biodynamic Simulation Models for Low Speed Collinear Rear Crash Conditions</title>
      <link>https://trid.trb.org/View/1825744</link>
      <description><![CDATA[Dynamic simulation is routinely used to analyze the occupant response to motor vehicle impact. That said, while commercially-available models have been subjected to numerous high-severity level validation studies, little attention has been given to lower severity crashes. While high severity crashes typically result in more severe injury, the vast numbers of lower severity “fender bender” type crashes and the ensuing high medical costs warrant study related to biomechanics and vehicle design. The scope of this study is directed at addressing the validity of these models for analyzing occupant response to collinear rear impact involving delta-V less than 5 mph. As part of this study, a series of five vehicle-to-vehicle collisions with instrumented volunteer occupants were performed with closing speeds of 1.1, 1.9, 2.9, 4.0 and 5.1 mph. These impacts produced delta-V, for the target vehicle, of 0.6, 1.8, 2.5, 3.1 and 3.2 mph, respectively. The measured response of the volunteer kinematics was compared with GATB simulation. Overall, the average percent discrepancy between the measured test data and the simulated values was 7.2 percent. With the exception of four instances, the percent discrepancy between the measured and simulated occupant response for each individual parameter was less than 10 percent. For the four instances where the difference between the measured and simulated values was greater than 10 percent, the simulated response consistently over-estimated the actual measured value in each case. Further, in the instances where the simulated response demonstrated and under-estimate of the measured value, the differences were small, exhibiting an average percent discrepancy of 4.3 percent. In addition, a parametric study of the influence of seat cushion stiffness to peak occupant response, demonstrated low sensitivity. Specifically, increasing the seat cushion stiffness 300 percent produces just a 22 percent increase in peak head acceleration. Similarly, the same seat cushion stiffness increases lead to increased peak chest and lumbar responses of 10 and 25 percent, respectively.]]></description>
      <pubDate>Thu, 09 Dec 2021 10:34:37 GMT</pubDate>
      <guid>https://trid.trb.org/View/1825744</guid>
    </item>
    <item>
      <title>A Study of Driver Injury Mechanism in High Speed Lateral Impacts of Stock Car Auto Racing Using a Human Body FE Model</title>
      <link>https://trid.trb.org/View/1823165</link>
      <description><![CDATA[This paper analyzed the mechanisms of injury in high speed, right-lateral impacts of stock car auto racing, and interaction of the occupant and the seat system for the purpose of reducing the risk of injury, primarily rib fractures.  Many safety improvements have been made to stock car racing recently, including the Head and Neck Support devices (HANS®), the 6-point restraint harnesses, and the implementation of the SAFER Barrier.  These improvements have contributed greatly to mitigating injury during the race crash event.  However, there is still potential to improve the seat structure and the understanding of the interaction between the driver and the seat in the continuation of making racing safety improvements.  This is particularly true in the case of right-lateral impacts where the primary interaction is between the seat supports and the driver and where the chest is the primary region of injury.  Currently, the driver kinematics and the interactions between the driver and the seat/restraint system at such high speeds are not clearly understood, due to the limitations of physical testing.  Therefore, for this study the Total HUman Model for Safety (THUMS) FE model was combined with a detailed NASCAR® cockpit and typical racing seat structure, in order to simulate the driver in a right-lateral high acceleration impact.  Simulations were conducted with two varied accelerations (25G and 70G), to judge the effect on injury risk.  Additionally, finite element (FE) simulations were run to investigate the risk of injury by varying chest support length, rigidity, and shoulder support vertical angles, representing the variability found in real-world racing seat structures.  For all of these simulations the distributed forces to the driver were analyzed and compared to injury tolerance limits found in literature.  Additionally, strain analysis of the cortical bone was used to estimate bone fracture risk.  By comparing all of the analysis results the most effective structure found to help reduce the possibility of rib fractures was that of a full rigid chest support structure (covering the length of the lateral ribs) with Energy Absorbing (EA) foam padding.  This allowed for optimum distribution of force across the lateral chest which prevented force concentration to local areas of the ribs.  It also provided a reduction in the applied shoulder force, hence, reducing the load to the clavicle.  This study successfully simulated high speed right lateral impacts using the human finite element model, THUMS, and demonstrated mechanisms of injury for rib fractures which can be improved upon through seat structure modifications to help reduce the risk of injury in such crashes.]]></description>
      <pubDate>Thu, 09 Dec 2021 10:34:07 GMT</pubDate>
      <guid>https://trid.trb.org/View/1823165</guid>
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