Browse Topic: Rear-end crashes

Items (173)
Prevention and diagnosis of traumatic brain injuries (TBI) are reliant on understanding the biomechanical response of the brain to external stimuli. Finite element models (FEM) and artificial head surrogates are becoming a common method of investigating the dynamic response of the brain to injurious impact and inertial stimuli. The accuracy and validity of these models is reliant on postmortem human subject (PMHS) research to produce biofidelic brain tissue responses. Previous PMHS research has been performed to measure intracranial pressures, displacements, and strains when subjected to impact and inertial loading; however, there remains a need for additional PMHS datasets to improve our understanding of the brain’s dynamics. The purpose of this study is to measure the relative brain–skull displacement in a PMHS specimen when subjected to blunt force impacts. A high-speed X-ray (HSXR) imaging system and embedded radiopaque elastomeric markers were used to record PMHS impacts at
Demiannay, Jean-JacquesRovt, JenniferBrannen, MacKenzieXu, ShengKang, GiaYip, AshleyAzadi, Amir HosseinDehghan, ParisaGoodwin, ShannonTaylor, ReggiePoon, KatherineBrien, SusanHoshizaki, BlaineKarton, ClaraPetel , Oren
Rear-end vehicle collisions may lead to whiplash-associated disorders (WADs), comprising a variety of neck and head pain responses. Specifically, increased axial head rotation has been associated with the risk of injuries during rear impacts, while specific tissues, including the capsular ligaments, have been implicated in pain response. Given the limited experimental data for out-of-position rear impact scenarios, computational human body models (HBMs) can inform the potential for tissue-level injury. Previous studies have considered external boundary conditions to reposition the head axially but were limited in reproducing a biofidelic movement. The objectives of this study were to implement a novel head repositioning method to achieve targeted axial rotations and evaluate the tissue-level response for a rear impact condition. The repositioning method used reference geometries to rotate the head to three target positions, showing good correspondence to reported interverbal rotations
Reis, Matheus SeifCronin, Duane
Forward-facing child restraint systems (FF CRS) and high-back boosters often contact the vehicle seat head restraint (HR) when installed, creating a gap between the back surface of the CRS and the vehicle seat. The effects of HR interference on dynamic CRS performance are not well documented. The objective of this study is to quantify the effects of HR interference for FF CRS and high-back boosters in frontal and far-side impacts. Production vehicle seats with prominent, removeable HRs were attached to a sled buck. One FF CRS and two booster models were tested with the HR in place (causing interference) and with the HR removed (no interference). A variety of installation methods were examined for the FF CRS. A total of twenty-four tests were run. In frontal impacts, HR interference produced small but consistent increases in frontal head excursion and HIC36. Head excursions were more directly related to the more forward initial position rather than kinematic differences caused by HR
Mansfield, Julie A.
India is a diverse country in terms of road conditions, road maintenance, traffic conditions, traffic density, quality of traffic which implies presence of agricultural tractors, bullock carts, autos, motor bikes, oncoming traffic in same lane, vulnerable road users (VRU) walking in the same lanes as vehicles, VRU’s crossing roads without using zebra crossings etc. as additional traffic quality deterrents in comparison to developed countries. The braking capacity of such vivid road users may not be at par with global standards due to their maintenance, loading beyond specifications, driver behavior which includes the tendency to maintain a close gap between the preceding vehicle etc. which may lead to incidents specifically of rear collisions due to the front vehicle going through an emergency braking event. The following paper provides a comprehensive study of the special considerations or intricacies in implementation of Autonomous Emergency Braking (AEBS) feature into Indian traffic
Kartheek, NedunuriKhare, RashmitaSathyamurthy, SainathanManickam, PraveenkumarKuchipudi, Venkata Sai Pavan
Highway safety remains a significant concern, especially in mixed traffic scenarios involving heavy-duty vehicles (HDV) and smaller passenger cars. The vulnerability of HDVs following closely behind smaller cars is evident in incidents involving the lead vehicle, potentially leading to catastrophic rear-end collisions. This paper explores how automatic speed enforcement systems, using speed cameras, can mitigate risks for HDVs in such critical situations. While historical crash data consistently demonstrates the reduction of accidents near speed cameras, this paper goes beyond the conventional notion of crash occurrence reduction. Instead, it investigates the profound impact of driver behavior changes within desired travel speed distribution, especially around speed cameras, and their contribution to the safety of trailing vehicles, with a specific focus on heavy-duty trucks in accident-prone scenarios. To conduct this analysis, we utilize SUMO, an open-source microscopic traffic
Shiledar, AnkurSujan, VivekSiekmann, AdamYuan, Jinghui
Automatic emergency braking and forward collision warning (FCW) reduce the incidence of police-reported rear-end crashes by 27% to 50%, but these systems may not be effective for preventing rear-end crashes with nonpassenger vehicles. IIHS and Transport Canada evaluated FCW performance with 12 nonpassenger and 7 passenger vehicle or surrogate vehicle targets in five 2021-2022 model year vehicles. The presence and timing of an FCW was measured as a test vehicle traveling 50, 60, or 70 km/h approached a stationary target ahead in the lane center. Equivalence testing was used to evaluate whether the proportion of trials with an FCW (within ± 0.20) and the average time-to-collision of the warning (within ± 0.23 sec) for each target was meaningfully different from a global vehicle car target (GVT). A similar approach was used to determine if FCW performance was reproducible between 3 targets tested by both IIHS and Transport Canada and was equivalent between surrogate car and motorcycle
Kidd, DavidAnctil, BenoitCharlebois, Dominique
In 2021, 412,432 road accidents were reported in India, resulting in 153,972 deaths and 384,448 injuries. India has the highest number of road fatalities, accounting for 11% of the global road fatalities. Therefore, it is important to explore the underlying causes of accidents on Indian roads. The objective of this study is to identify the factors inherent in accidents in India using clustering analysis based on self-organizing maps (SOM). It also attempts to recommend some countermeasures based on the identified factors. The study used Indian accident data collected by members of ICAT-ADAC (International Centre for Automotive Technology - Accident Data Analysis Centre) under the ICAT-RNTBCI joint project approved by the Ministry of Heavy Industries, Government of India. 210 cases were collected from the National Highway between Jaipur and Gurgaon and 239 cases from urban and semi-urban roads around Chennai were used for the analysis. Based on this study, the following results were
Vimalathithan, KulothunganRao K M, PraneshVallabhaneni, PratapnaiduSelvarathinam, VivekrajManoharan, JeyabharathPal, ChinmoyPadhy, SitikanthaJoshi, Madhusudan
This study was conducted to assess the occupant restraint use and injury risks by seating position. The results were used to discuss the merit of selected warning systems. The 1989-2015 NASS-CDS and 2017-2021 CISS data were analyzed for light vehicles in all, frontal and rear tow-away crashes. The differences in serious injury risk (MAIS 3+F) were determined for front and rear seating positions, including the right, middle and left second-row seats. Occupancy and restraint use were determined by model year groups. Occupancy relative to the driver was 27% in the right-front (RF) and 17% in the second row in all crashes. About 39% of second-row passengers were in the left seat, 15% in the center seat and 47% in the right seat. Restraint use was lower in the second row compared to front seats. It was 43% in the right-front and 32% in the second-row seats in all crashes involving serious injury. Restraint use increased with model year groups. It was 63% in the ‘61-‘89 MY vehicles and 90
Parenteau, ChantalBurnett, Roger
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
Bussone, William R.Koiler, RezaBenda, JamieCarney, NicholasGeffard, AndresSam, Samantha
The Bendix Wingman Fusion – a radar and camera collision mitigation system (CMS) available on commercial vehicles – was evaluated in two separate test series to determine its performance in simulated rear collision scenarios. In the first series of tests, evaluations were conducted in daytime, nighttime, and rainy conditions between 15 to 58 miles per hour (mph) to evaluate the performance of the audible and visual forward collision warning (FCW) system in a first-generation Bendix Wingman Fusion CMS while approaching a stationary live vehicle target (SLVT) in a 2017 Kenworth T680. A second test series was conducted with a 2017 Kenworth T680 traveling at 50 mph in daytime conditions approaching a decelerating vehicle to evaluate the Bendix Wingman Fusion CMS on the truck. Both test series sought to determine the maximum distance the system would warn prior to the test driver swerving around the SLVT or moving vehicle target. The first test series utilized a 2014 Ford F150 as the SLVT
Harrington, ShawnMartin, NicholasLeiss, Peter
The accuracy of collision severity data recorded by event data recorders (EDRs) has been previously measured primarily using barrier impact data from compliance tests and experimental low-speed impacts. There has been less study of the accuracy of EDR-based collision severity data in real-world, vehicle-to-vehicle collisions. Here we used 189 real-world front-into-rear collisions from the Crash Investigating Sampling System (CISS) database where the EDR from both vehicles recorded a severity to examine the accuracy of the EDR-reported speed changes. We calculated relative error between the EDR-reported speed change of each vehicle and a speed change predicted for that same vehicle using the EDR-reported speed change of the other vehicle and conservation of momentum. We also examined the effect of vehicle-type, mass ratio, and pre-impact braking on the relative error in the speed changes. Overall, we found that the common practice of using the bullet vehicle’s EDR-reported speed change
Fix, RyanWilkinson, CraigSiegmund, Gunter P.
Seatback and head restraints are the primary restraining devices in rear-impact collisions. The seatback failures expose front seat occupants to dive deep into the rear compartment survival space. Furthermore, it allows the occupants to get in a position with lower spinal tolerance to the impact direction. This paper employs sled tests to demonstrate the dangers of seatback failures in severe rear impact by allowing the occupants to orient their spine in its lowest tolerance zone to the impact direction. Furthermore, the sled test shows the potential of head pocketing phenomena and torso augmentation producing compressive cervical spine loading enough to cause first-order neck buckling. Finally, the results of collapsing seatback dynamics are compared to the strong seatback performance by conducting a similar test with a strong ABTS seatback. The study demonstrates that the strong seatbacks in severe rear impacts produce favorable outcomes while keeping the occupant in their higher
Thorbole, Chandrashekhar
Child crash injury protection in severe rear impact chiefly depends on how well the rear survival space bounded by the vehicle structure is maintained. Previous research and studies have shown the ill effects of front seatback collapse intruding into the rear child survival space from front with minor or no intrusions from the rear. This paper shows the child injury pattern and fatal injury mechanism for a rear impact crash with a severe compartment intrusion from the rear without any front seat occupant. Furthermore, it compares the injury outcome with a similar crash and severe intrusion in the presence of the front occupant employing a full-scale vehicle-to-vehicle crash test. A detailed real-world crash investigation is conducted to identify the injury mechanism and is compared with the outcome of similar severity rear impact vehicle-to-vehicle crash tests producing different injury patterns. The comparison and the analysis show that the survival space intrusion due to safety cage
Thorbole, Chandrashekhar
The key issues of automatic emergency braking (AEB) control algorithm are when and how to brake. This article proposes an AEB control algorithm that integrates risk perception (RP) and emergency braking characteristics of professional drivers for rear-end collision avoidance. Using the formulated RP by time to collision (TTC) and time headway (THW), the brake trigger time can be determined. Based on the professional driver fitting (PDF) characteristic, the brake pattern can be developed. Through MATLAB/Simulink simulation platform, the European New Car Assessment Programme (Euro-NCAP) test scenarios are used to verify the proposed control algorithm. The simulation results show that compared with the TTC control algorithm, PDF control algorithm, and the integrated PDF and TTC control algorithm, the proposed integrated PDF and RP control algorithm has the best performance, which can not only ensure safety and brake comfort, but also improve the road resource utilization rate
Lai, FeiHuang, ChaoqunJiang, Chengyue
This work aimed to analyze the behavior of the rear structure region of an electric bus in a rear collision situation and to create mechanisms capable of absorbing the energy generated by the impact, to guarantee the integrity of the batteries. These, when damaged in a collision, can release different types of flammable electrolytes, and even start a fire, creating a great risk to passengers and other people near to the vehicle. For this purpose, an impact absorber was developed to protect the batteries. Studies were carried out on rectangular cross-section profiles for programmed deformation, known as crash boxes (which aim to convert kinetic energy into deformation energy). Proposals were created based on concepts obtained in the literature and numerically evaluated through explicit numerical simulations based on other similar articles. From these studies it was possible to obtain higher values of energy absorption when compared to a square tube of the same cross-section. After the
Menino, Bruno G.Spengler, FelipeBiondo, Felipe
In order to reduce collision at a 90-degree intersection, an automatic emergency collision avoidance control method for intelligent vehicles based on vehicle-to-everything (V2X) technology is proposed. Most of the existing automatic emergency braking (AEB) control algorithms are designed for a single high-friction road with reference to the European New Car Assessment Programme (Euro NCAP) evaluation procedures, and they do not consider changes in road friction. Thus, it may be difficult to avoid collision successfully on a low-friction road. Although some studies have considered the variation of road friction, they are only applicable to straight-line rear-end collisions and cannot be directly applied to intersections. In addition, most studies regard the vehicle only as a particle, ignoring the actual dynamic characteristics of the vehicle. The main contribution of this article is to present an AEB control strategy by V2X technology, which can make the intelligent vehicle avoid
Lai, FeiYang, HuiHuang, Chaoqun
Testing was conducted in daytime conditions at four speeds – 35, 50, 60, and 70 mph – to evaluate the performance of the audible and visual forward collision warning (FCW) component of the collision mitigation system in a 2016 Volvo XC90 while approaching a stationary vehicle target (SVT) in a rear collision scenario. Testing measured the time to collision (TTC) values at the issuance of the FCW, the distance from the test Volvo to the SVT at FCW, and the speed of the Volvo at FCW utilizing Racelogic VBOX data acquisition systems. The results of the testing add higher speed scenarios to the database of publicly available tests from sources like the Insurance Institute for Highway Safety (IIHS), which currently evaluates vehicles at 12 and 25 mph. In addition, the timing and accelerations of evasive steering maneuvers relative to the SVT were quantified
Harrington, ShawnHandzic, Dino
The concept of a seat with an active adjustable seatback stiffness for enhanced safety during a rear impact was published previously. Static testing of a demonstrative prototype is supplemented with repeated dynamic tests at various velocity / acceleration levels. These tests were performed with a Hybrid III Anthropomorphic Test Device (ATD) and demonstrate that the occupant response can be modified by engagement of the device based on the severity of the crash pulse and other factors. A mathematical model for the dynamic response of the seat and the correlated occupant response is in development. Refinement of this technology is complemented by results of the dynamic testing
Warner, WyattWarner, Mark
Testing was conducted to evaluate the effect on the Time to Collision (TTC) values of the visual and audible components of the Forward Collision Warning (FCW) provided by a 2017 Honda CR-V by changing the user-selected FCW Distance between Long, Normal, and Short. As part of the Honda Sensing Collision Mitigation Braking System (CMBSTM), these user-selected values change the timing of the issuance of the visual and audible warning provided to drivers. This testing evaluated the Honda at speeds of 20, 35, 50, 60, and 65 miles per hour (mph) versus a stationary live vehicle in daytime conditions in a simulated rear collision scenario. Different FCW distance settings were selected to compare the response of the system at the 20 – 65 mph range of speeds. The TTC at FCW and the distance between the Honda and the target at FCW are presented and compared at each speed and user-selected FCW Distance setting. A subset of the current research – the 20- and 35-mph tests – were compared to testing
Harrington, ShawnNagarajan, Sundar RamanLau, James
The coefficient of restitution is utilized in various methods for determining the change in velocity (delta-V) associated with a vehicle collision event. Additionally, for a given delta-V, the magnitude of vehicle acceleration varies with different collision pulse durations. Collision restitution and duration parameters are thus considered by both accident reconstructionists and biomechanists in the investigation of vehicle collision severity and occupant injury potential. Because of the uniqueness of individual vehicle designs, it is difficult to determine a collision’s specific coefficient of restitution and crash pulse duration. Accident reconstructionists often estimate the values of these parameters based on staged crash tests. Prior studies involving low-speed collisions have sought to determine correlations between restitution and collision characteristics and have established equations to assist in estimating restitution. Most of these equations are based around the correlation
Olberding, JosephPetroskey, KarlaLeipold, Tara
Forward Collision Warning System is an important part of vehicle active safety system, it can reduce the occurrence of rear-end collision accidents with high fatality rate and improve the safety of driving. At present, there are still some outstanding issues to be addressed among the existing forward collision warning systems, such as the high cost of information acquisition based on LiDAR and other high-definition sensors, and the poor real-time performance of target detection based on vision. In view of the aforementioned issues and in order to improve the detection accuracy and real-time requirements of the target detection function of the early warning system, this paper proposes an enhanced deep learning model-based vehicle target detection method, and improves the key techniques of target detection, ranging and speed measurement and early warning strategy in the warning system. Then, a target positioning scheme by visual fusion method is employed to improve the accuracy of
Zhan, ZhenfeiZhou, GuilinFengyao, LVXue, BingyingHe, XinWang, JuLi, Jie
The Bendix Wingman Advanced – a radar-only collision mitigation system (CMS) available on commercial vehicles – was evaluated in two separate test series to determine its performance in simulated stationary vehicle rear collision scenarios. In the first series of tests, evaluations were conducted in daytime and nighttime conditions at two speed ranges – 35 and 45-50 miles per hour (mph) – to evaluate the performance of the audible and visual forward collision warning (FCW) system in a Bendix Wingman Advanced CMS while approaching a stationary vehicle target (SVT) in a 2018 International 4300. Two years later, a second test series was conducted with a 2019 International 4300 traveling between 15 – 55 mph in low light and nighttime conditions approaching the SVT to evaluate the Bendix Wingman Advanced CMS on the truck. Both test series sought to determine the maximum speed the system would warn prior to the test driver swerving around the SVT. The tests utilized a foam stationary vehicle
Harrington, ShawnLieber, Victoria
An analysis of peak lumbar load data collected from the existing peer-reviewed literature on rear impact crash tests was performed. Values for peak lumbar tension/compression, peak lumbar sagittal forces, and peak lumbar flexion/extension moments were aggregated from each study. The trends in the accumulated data were analyzed as functions of the changes in velocity (delta-Vs) measured during the crash tests. The data were further analyzed to identify differences in trends found across variations in the testing conditions used across studies. These testing conditions included type of anthropometric test device (ATD) used, type of ATD pelvis used, ATD seating position, production year of seat used, type of seat used, and type of seat restraint used. Data were also aggregated from peer-reviewed research quantifying peak lumbar compression in human subjects performing various tasks, including activities of daily living (ADLs), tasks related to sports and exercise, and industrial tasks
Kashdan, AryehUmale, SagarKazmierczak, AlexKasselik, JosephRandles, BryanFurbish, ChristopherWelcher, Judson
The Aft Collision Assist (ACA) is an Advanced Driver Assistance System (ADAS) that is added to a vehicle and integrates with the native systems of that vehicle. The ACA is used to monitor and reengage a distracted driver of an approaching vehicle that the ACA system calculates will imminently rear-end the host vehicle. This work provides a brief overview of existing ADAS that perform similar functions, the regulatory statutes and requirements that impact the ACA functionality, and Model-Based System Engineering (MBSE) model diagrams of the ACA. The MBSE model diagrams presented are State Machine, Conceptual Data Model, Use Case, System Requirements, and Regulatory Requirements for the entire ACA system. The MBSE models and regulatory constraints presented within are used to refine and specify the ACA method of attracting a distracted driver’s attention
Rictor, AndrewChandrasekar, Chandra V.
An improved control method of automatic emergency braking (AEB) for rear-end collision avoidance is proposed, which combines the advantages of a time-to-collision (TTC) control algorithm and professional driver emergency braking behavior. The TTC control algorithm mostly adopts phased braking, and although it can avoid collision effectively, the braking process is radical and brake comfort is poor. The emergency braking system with professional driver fitting (PDF) has good comfort and can also avoid collision successfully. However, its brake trigger time is too early, which leads to the stopping distance being too large under high-speed conditions and affects the road utilization. By combining the advantages of the two control methods, an improved control algorithm for AEB is proposed. When the TTC value is not greater than a predetermined limit, the PDF control switch will be closed to avoid collision. Through the Matlab/Simulink and CarSim co-simulation platform, the European New
Lai, Fei
The Autonomous emergency braking system (AEB) has been widely equipped in the design and manufacture of vehicles as an active safety system for preventing rear-end collisions. It has shown great safety potential in preventing collisions and reducing collision injuries. However, there are differences in the response characteristics of drivers in emergency scenarios due to individual differences and driving habits. The impact of different driver types on the safety performance of AEB systems has not been evaluated. In this study, the typical driver response model was constructed by selecting driver response features representing alertness and braking. The AEB algorithm of distance and situation awareness was combined with the kinematic of vehicle before the collision to construct a simulation case based on the rear-end collisions in the China in-depth accident study database (CIDAS). The collision avoidance percentage, the impact speed, and the minimum relative distance were used as
Wei, TianzhengKang, KaiZhu, TongLiu, Haoxue
This article compares the results of automotive accident reconstructions to event data recorder (EDR) data from vehicles involved in rear-end collisions. Accident reconstructions in the Crash Investigation Sampling System (CISS) database calculate crash severity expressed as the impact-related change in velocity (delta-V) experienced by a vehicle. The accuracy of the CISS-reconstructed delta-V in rear impacts was assessed by comparison to the delta-V recorded during the crash by the EDR on board the rear-ended vehicles. The CISS database was searched for single rear impact cases with a CISS-reconstructed delta-V as well as an EDR download. A total of 256 cases met these criteria. On average, the CISS-reconstructed delta-V was 4.0% lower than the delta-V recorded by the EDR. The accuracy of the CISS reconstructions varied with crash configuration, vehicle type, collision partner, and crash severity. Crash severity had the largest effect on accuracy, with low-speed reconstructions
Watson, RichardCormier, JosephBonugli, EnriqueGreenston, Mathew
This SAE Recommended Practice describes the test procedures for conducting rear impact occupant restraint and equipment mounting integrity tests for ambulance patient compartment applications. Its purpose is to describe crash pulse characteristics and establish recommended test procedures that will standardize restraint system and equipment mount testing for ambulances. Descriptions of the test set-up, test instrumentation, photographic/video coverage, and the test fixtures are included
Truck Crashworthiness Committee
This SAE Recommended Practice describes the testing procedures required to evaluate the integrity of a ground ambulance-based patient litter, litter retention system, and patient restraint when exposed to a frontal, side or rear impact. Its purpose is to provide litter manufacturers, ambulance builders, and end-users with testing procedures and, where appropriate, acceptance criteria that, to a great extent ensures the patient litter, litter retention system, and patient restraint utilizes a similar dynamic performance test methodology to that which is applied to other vehicle seating and occupant restraint systems. Descriptions of the test set-up, test instrumentation, photographic/video coverage, test fixture, and performance metrics are included
Truck Crashworthiness Committee
This SAE Recommended Practice describes the dynamic testing procedures required to evaluate the integrity of patient compartment interior Storage Compartments such as cabinets, drawers, or refillable supply pouch systems when exposed to a frontal, side or rear impact (i.e., a crash impact). Its purpose is to provide component manufacturers, ambulance builders, and end-users with testing procedures and, where appropriate, acceptance criteria that, to a great extent, ensure interior Storage Compartments or systems meet the same performance criteria across the industry. Descriptions of the test set-up, test instrumentation, photographic/video coverage, test fixture, and performance metrics are included
Truck Crashworthiness Committee
This SAE Recommended Practice describes the dynamic and static testing procedures required to evaluate the integrity of the ambulance substructure, to support the safe mounting of an SAE J3027 compliant litter retention device or system, when exposed to a frontal, side or rear impact (i.e., a crash impact). Its purpose is to provide manufacturers, ambulance builders, and end-users with testing procedures and, where appropriate, acceptance criteria that to a great extent ensure the ambulance substructure meets the same performance criteria across the industry. Prospective manufacturers or vendors have the option of performing either dynamic testing or static testing. Descriptions of the test set-up, test instrumentation, photographic/video coverage, test fixture, and performance metrics are included
Truck Crashworthiness Committee
Vehicles with automated driving systems (ADS) may allow nontraditional seating arrangements, such as a reclined seat that is rear facing in a frontal impact. Currently, there is not a widely accepted, commercially available, anthropomorphic test device (ATD) that is designed for a reclined, rear-facing, high-speed crash situation. To begin to identify what modifications are needed for candidate ATDs to exhibit human-like characteristics in these nontraditional scenarios, ATDs should be tested and compared to available postmortem human subject (PMHS) biofidelity response corridors in these seating arrangements. The first objective of this study was to present and discuss updates to the Biofidelity Ranking System (BRS). The second objective was to use the updated BRS to evaluate the responses of the THOR 50th percentile male (Test device for Human Occupant Response, THOR-50M) ATD in the rear-facing condition. Quantitative comparisons were made between the THOR responses and biofidelity
Hagedorn, AlenaStammen, JasonRamachandra, RakshitRhule, HeatherThomas, ColtonSuntay, BrianKang, Yun-SeokKwon, Hyun JungMoorhouse, KevinBolte IV, John H.
The risk for severe injury (MAIS 4+F) was determined by crash type, seatbelt use and crash severity (delta V) using 22 years of NASS-CDS from 1994-2015 with all light vehicles and occupants 15+ years old. There were 9 increments of delta V from <16-72+ km/h (<10-45+ mph). Crashes were grouped by the location of damage to the front, near-side, far-side and rear. Injury risk was calculated by dividing the number of severely injured (MAIS 4+F) by the number of exposure (MAIS 0+F) occupants using weighted data. Standard errors were determined. The data and plots provide a national estimate of injury by delta V in front, near-side, far-side and rear impacts based on the multi-year field data in NASS-CDS
Viano, DavidParenteau, Chantal
This paper proposes a new method to improve the fit between the neck finite element calculation results and the experimental data through multi-objective optimization of cervical ligament parameters. By refining a previously established finite element model of the neck and improving the fineness of vertebrae and other structures, a new finite element model of the neck was established. The new model adopts the same material property parameters as the previous model. We performed many simulation calculations, each time only one ligament in the model was removed, leaving other structures unchanged. By observing the changes in the angle of the neck joints in the neck torsion experiment of the model before and after the ligament was removed, the influence of the ligament on the model was obtained. The six ligaments with the largest contribution are selected, and their laxity is optimized for multi-objective research, and the optimal solution for the laxity of the selected ligaments is
Yang, ShuaijunSong, XueweiWang, PengWang, Nan
Prior to developing or modifying the protocol of a performance evaluation test, it is important to identify field relevant conditions. The objective of this study was to assess the distribution of selected crash variables from rear crash field collisions involving modern vehicles. The number of exposed and serious-to-fatally injured non-ejected occupants was determined in 2008+ model year (MY) vehicles using the NASS-CDS and CISS databases. Selected crash variables were assessed for rear crashes, including severity (delta V), impact location, struck vehicle type, and striking objects. In addition, 15 EDRs were collected from 2017 to 2019 CISS cases involving 2008+ MY light vehicles with a rear delta V ranging from 32 to 48 km/h. Ten rear crash tests were also investigated to identify pulse characteristics in rear crashes. The tests included five vehicle-to-vehicle crash tests and five FMVSS 301R barrier tests matching the struck vehicle. The analysis of NASS-CDS and CISS data indicates
Parenteau, ChantalWhite, SamuelBurnett, RogerStephens, GregoryMichalski, David
This study was conducted to assess the effects of differing rear impact pulse characteristics on restraint performance, front-seat occupant kinematics, biomechanical responses, and seat yielding. Five rear sled tests were conducted at 40.2 km/h using a modern seat. The sled buck was representative of a generic sport utility vehicle. A 50th percentile Hybrid III ATD was used. The peak accelerations, acceleration profiles and durations were varied. Three of the pulses were selected based on published information and two were modeled to assess the effects of peak acceleration occurring early and later within the pulse duration using a front and rear biased trapezoidal characteristic shape. The seatback angle at maximum rearward deformation varied from 46 to 67 degrees. It was lowest in Pulse 1 which simulates an 80 km/h car-to-car rear impact. The seatback plastic deformation was greater in the pulse with the rear biased trapezoidal acceleration profile, Pulse 4, than in the front biased
Parenteau, ChantalWhite, SamuelBurnett, Roger
The THOR-AV dummy is a modified THOR dummy being developed for occupant safety testing in upright and reclined seating postures. The dummy has a new neck with improved biofidelity in rear impact, a pelvis/abdomen/lumbar design to improve seating posture, and a pelvis anthropometry that mimics human submarining responses for reclined seat testing. The dummy was evaluated against postmortem human subject (PMHS) corridors in rearward facing impact conditions (56 km/h impact speed, 38g acceleration) in both 25° and 45° seatback configurations. Biofidelity Ranking System (BRS) scores were calculated in accordance with NHTSA’s latest calculation algorithm. The BRS scores for THOR-AV seat loading are 1.58 (“good” biofidelity) and 2.94 (“marginal” biofidelity) for the 25° and 45° configurations respectively. The BRS scores for THOR-AV occupant responses are 1.95 and 1.38 for the 25° and 45° configurations respectively, both corresponding to “good” biofidelity. From the evaluation, the dummy
Wang, Zhenwen Jerry
Development of a seat with an active adjustable seatback stiffness for enhanced safety during a rear impact is demonstrated. Review of literature suggests that there is not a single value for seatback stiffness to optimize occupant protection. An automobile seat whose stiffness can be actively adjusted based on EDR input and other factors can potentially enhance occupant safety during some rear impact crashes. Static pull tests were performed using a prototype seat demonstrating how seatback stiffness can be modified, and deformation limited, using electromechanical means. Research and development of this technology is ongoing
Warner, Wyatt Y.Warner, Mark H.
Field data was analyzed on second-row children in front, side and rear impacts to study fatality trends by model year (MY) and calendar year (CY) with 1980-2020 MY vehicles. The different MY and CY perspectives show changes in rates that are useful for setting priorities for second-row child safety in rear impacts. 1990 to 2019 FARS was queried to assess the number of fatally injured and non-ejected second-row children (0-15 years old) in crashes without fires. The children included outboard occupants seated behind an occupied front seat and center occupants. The data was analyzed for rear, front and side impacts to assess crash frequency. 1990-2015 POLK was queried to assess exposure of registered vehicles and estimate a fatality rate. The FARS and POLK data were sub-grouped by MY of the vehicle and CY of the crash. There were 2.8-times more fatally injured children in frontal crashes than in the rear crashes. The ratio of frontal and rear crashes varied with CY sub-groups. It was 3.9
Parenteau, ChantalViano, DavidLau, Edmund
Four crash modes are overrepresented in traffic fatalities: run-off-road crashes, non-tracking run-off-road crashes, head-on crashes, and pedestrian crashes. Two advanced driver assist systems developed to help prevent tracking run-off-road crashes and head-on crashes are lane departure warning (LDW) and lane keeping assist (LKA). LDW acts to warn the driver when they are encroaching the lane boundary, whereas LKA performs automatic steering to prevent the vehicle from departing the lane. The objective of this research was to use real-world crash data to estimate current LDW and LKA system effectiveness in reducing run-off-road crashes and cross-centerline head-on crashes. All passenger vehicles that experienced a lane departure from 2017 to 2019 in the Crash Investigation Sampling System (CISS) were analyzed. The effectivenesses of the LDW and LKA systems were computed using the quasi-induced exposure method, where the exposure group was vehicles that were rear-struck in rear-end
Dean, Morgan E.Riexinger, Luke E.
Vehicle rear structure stiffness has increased as a result of the requirements in the FMVSS 301R, which has also corresponded to an increase in front-row seat strength. This study evaluates the structural behavior and occupant response associated with production-level seats equipped with body-mounted D-rings, and very stiff all-belt-to-seat (ABTS) in a group of 12 deceleration sled tests. A double-haversine pulse with approximately 100-msec duration was used for all tests, with peak accelerations of approximately 19 g for the 40 km/h (25 mph) tests and peak accelerations of 28 g for the 56 km/h (35 mph) test. This generic pulse was designed to represent a severe rear impact crash involving vehicles with stiffer rear structures. The tests compared occupant responses and resulting structural deformation of an original equipment manufacturer (OEM) production-level driver seat from a pickup and a very stiff modified ABTS. Both seating systems were equipped with dual recliners. Various
Croteau, JeffreyToney-Bolger, MeganIsaacs, Jessica L.Shurtz, BenZolock, John
In rear-end collisions, the seatback provides primary occupant restraint during initial rearward motion of the occupant relative to the vehicle interior as the vehicle is accelerated forward by collision forces. When properly used, seat belts contribute to limiting occupant excursion and loading by working in concert with the seatback, as well as managing forward excursion on rebound after rear-end impacts. A lack of data evaluating the role of seat belt restraint component technology in limiting occupant motion and loading during high-severity rear-end impacts has been identified. This knowledge gap is particularly apparent for occupants who are not seated normally, in position, at the time of impact. Previous static pretensioner deployment tests suggest that different combinations of latch plate design and pretensioner deployment strategies might have different effects on occupant restraint. In this study, dynamic sled tests (40 km/h) were conducted to assess how various combinations
Toney-Bolger, MeganIsaacs, Jessica L.Rapp van Roden, ElizabethCroteau, JeffreyDibb, Alan
A novel, electrically self-propelled, mobile, free-standing crash sled was constructed with a relatively minimal budget (i.e., ≤ $10,000). The crash sled was designed to simulate occupant driver or passenger seat movement in minor impacts at varying angles with minimal, if any, component replacement necessary between tests. Validation of the crash sled in a rear-end only configuration for determination of occupant accelerations was performed. Minor rear-end crash tests involving human occupants were conducted utilizing a 2007 Toyota Camry target vehicle and a 2005 Toyota Camry bullet vehicle with changes in velocity for the target vehicle ranging between 2.8 km/h and 7.7 km/h. Vehicle instrumentation consisted of tri-axial accelerometers affixed to the center tunnels near their respective center of gravities. Human occupant instrumentation occurred only in the target vehicle and involved tri-axial accelerometers at the head, thorax, and lumbar spine. Peak longitudinal head and lumbar
Vigil, Cole MackenzieSalboro, ConradJorgensen, MichaelJones, BrianBrink, JustinSwinford, Scott
An automated driving system (ADS) shall provide safer conditions for highly automated vehicle (HAV) users compared to standard vehicles since human error is excluded. In the following decades, however, one can expect a mixed fleet of both standard and automated vehicles on roads. Therefore, collisions between manually driven cars and HAVs are to be expected. On the other hand, HAVs’ occupants access more room in the vehicle which allows them to rotate their seats to have a comfortable position. This work aims to address the issue of HAV’s occupant safety using tools of numerical simulations. We consider an FE model of a seat with the standard three-point belt at two initial orientations 45° and 90°. The occupant (50th percentile male) is represented with the Virthuman model. We test the idea of employing the active seat rotation system. By detecting a crash well in time an initially rotated seat is reoriented into a standard seating orientation in a rear-end crash. To improve the
Talimian, AbbasVychytil, Jan
Detailed finite element human body models (HBMs), and neck models (NMs) in particular, have been used to assess response and injury risk with a focus on frontal, lateral, and rear impact conditions. Although HBMs have successfully predicted kinematics and the importance of active muscle in simple loading conditions, they have generally not been assessed for more complex loading conditions such as non-traditional oblique loading that may be encountered in future vehicles equipped with automated driving systems. In this study, a contemporary NM was assessed using oblique human volunteer sled test data. Average head and first thoracic vertebra kinematics were determined from the volunteer tests and applied as a boundary condition to the NM. An open-loop co-contraction muscle activation scheme with four activations times within reported human limits (50, 75, 100, no activation) was used to investigate the effect on response and potential for injury risk. The T1 and head kinematics from 45
Barker, JeffreyCronin, Duane S.
Child safety in the back seat during a rear-impact chiefly depends on how well the survival space is maintained at their location. Collapsing front seatback pose a foreseeable hazard as it intrudes into the survival space of the child on the backseat. Furthermore, the condition gets worse in the presence of a structural intrusion from the rear that tends to push the occupant further closer to the backward collapsing seatbacks. This paper reports two real-world rear impact collisions resulting severe to fatal injuries to the child occupant seating behind the driver. Each collision shows the dangers of seatback collapse into the survival space of the child. Furthermore, the paper demonstrates safety through design concept by employing seats with strong seatback design resisting collapse into the survival space of the child. The crash sled-testing are conducted to show the importance of front seatback strength preventing its collapse and occupant ramping up into the child’s survival space
Thorbole, Chandrashekhar
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