Browse Topic: Rear-end crashes

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Feasibility of Road Longitudinal Profiles for Automated Vehicles Based on Vehicle Dynamics2025-01-715003/19/2025
With the development and maturity of new generation digital technologies such as artificial intelligence, Internet of Things, and 5G mobile communication, their integration with physical products is becoming increasingly seamless. Automobiles serve as a prime example in this regard. In recent years, automated vehicle (AV) technologies have emerged as a prominent focal point, witnessing an escalating acceptance in the market and a growing number of self-driving vehicles on the roads, existing roads are primarily designed for traditional human-driven vehicles (HVs). Due to the differences in perception between automated systems and human drivers, it is essential to assess AVs' feasibility to current road infrastructure. This paper analyzes the safety and comfort of automated vehicles equipped with adaptive cruise control systems (ACC-AVs) on longitudinal road profiles from the perspective of vehicle dynamics. Firstly, a co-simulation platform integrating PreScan, CarSim, and Simulink
Li, Zezhou, Cai, Mingmao, Gu, Tianqi, Yu, Bin
Seatback Failures and Human Tolerance in Severe Rear Impacts2024-26-000301/16/2024
Seatback and head restraints is the primary restraining device 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 Injury Pattern and Mechanism Differences Based on the Front Seat Occupancy Status in Rear Impacts with Severe Structural Intrusions from the Rear2024-26-000501/16/2024
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 the 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. It 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
Thorbole, Chandrashekhar
Rear-End Impacts – Part 2: Sled Pulse Effect on Front-Seat Occupant Responses 2022-01-103903/29/2022
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 km/h using a modern seat. The sled buck was representative of a mid-sized driver environment in a generic sport utility vehicle. The peak acceleration, acceleration shape and duration were varied. Three of the pulses were selected based on published information and two were calculated to assess the effects of long and short initial acceleration rate using a trapezoidal characteristic shape. The angle at maximum seatback rearward deformation varied from 26 to 47 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 a long initial acceleration rate, Pulse 4, than in the short acceleration rate, Pulse 5 (28 degrees v 22 degrees). Coincidingly, the longitudinal
Parenteau, Chantal, White, Samuel, Burnett, Roger
Injury by Delta V in Front, Near-Side, Far-Side and Rear Impacts: Analysis of 1994-2015 NASS-CDS 2022-01-100803/29/2022
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 most recent field data in NASS-CDS.
Viano, David, Parenteau, Chantal
Seatback Strength and its Effect on In Position and Out of Position ATD Loading in High-Speed Rear Impact Sled Tests 2022-01-103803/29/2022
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 approximately 100-msec duration pulse 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 pulse was designed to represent a severe rear impact crash involving modern vehicles. 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 combinations of tests evaluated the
Croteau, Jeffrey, Toney-Bolger, Megan, Isaacs, Jessica L., Shurtz, Ben, Zolock, John
Rear-End Impacts – Part 1: Field and Test Data Analysis of Crash Characteristics 2022-01-104103/29/2022
Prior to developing or modifying the protocol of performance evaluation tests, 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 accidents involving modern vehicles. The exposure and serious-to-fatal injury of non-ejected occupants was determined in 2008+ model year (MY) vehicles using 2007-2015 NASS-CDS and 2017-2019 CISS. In addition, 15 EDRs were collected from 2017 to 2019 CISS cases with a rear delta V ranging from 32 to 48 km/h. Ten rear crash tests were also investigated to identifying 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 that more than 50% of exposed (MAIS 0+F) occupants were involved in a rear crash with a distributed impact and with no over-ride or under-ride. More than 93% were with a 6 o’clock
Parenteau, Chantal, White, Samuel, Burnett, Roger, Stephens, Gregory, Michalski, David
Development of a Variable Stiffness Seatback2022-01-103703/29/2022
A challenge faced by the automotive industry is to optimize the stiffness of seat structures such that in rear-impact collisions, seatback deflection is compliant enough to adequately absorb impact energy, yet stiff enough to prevent excess deformation. While comprising a smaller percentage of all automotive accidents, severe and fatal injuries occur in rear impact crashes. Injuries to front seat passengers can be mitigated in some crashes with stiffer seatbacks, and in other crashes with more yielding seatbacks, depending on the accident severity and other factors. In rare cases, injuries to rear seat passengers occur when front seats deform and intrude into rear occupant spaces. There has existed a debate for years regarding whether seats should be manufactured increasingly stiffer, or more yielding. Compounding the problem are additional factors including widely varying crash severities, impact angles, out-of-position occupants, intermittent use of rear seating areas, etc
Warner, Mark H., Warner, Wyatt
Validation of Utilizing a Self-Propelled Crash Sled to Simulate Occupant Accelerations in Minor Rear-End Impacts2022-01-104003/29/2022
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 Mackenzie, Salboro, Conrad, Jones, Brian, Brink, Justin, Jorgensen, Michael, Swinford, Scott
Incidence and Mechanisms of Head, Cervical Spine, Lumbar Spine, and Lower Extremity Injuries for Occupants in Low- to Moderate-Speed Rear-End Collisions2021-01-090004/06/2021
Automotive accidents and subsequent personal injury claims incur substantial costs annually. While seat and head restraint design continue to evolve and improve, occupant safety and injury risk assessment in rear-end collisions remain at the forefront of automotive innovation. In this study, we combined statistical analyses of nine years (2007-2015) of data from the National Automotive Sampling System Crashworthiness Data System (NASS-CDS) database and one year (2017) of data from the Crash Investigation Sampling System (CISS) database with data acquired from vehicle-to-vehicle crash tests conducted with instrumented anthropomorphic test device (ATD) occupants. Together, these analyses were used to compare and relate field injury rates with potential mechanisms underlying head, cervical spine, lumbar spine, and lower extremity injuries in low-to moderate-speed rear-end collisions. First, we performed statistical analyses of the NASS-CDS and CISS databases to estimate the rate of AIS 2
Davis, M., Mkandawire, C., Brown, T., Pasquesi, S.
Dual-Recliner ABTS Seats in Severe Rear Sled Testswith the 5th, 50th and 95th Hybrid III2021-01-091704/06/2021
Seat strength has increased over the past four decades which includes a transition to dual recliners. There are seat collision performance issues with stiff ABTS and very strong seats in rear impacts with different occupant sizes, seating positions and physical conditions. In this study, eight rear sled tests were conducted in four series: 1) ABTS in a 56 km/h (35 mph) test with a 50th Hybrid III ATD at MGA, 2) dual-recliner ABTS and F-150 in a 56 km/h (35 mph) test with a 5th female Hybrid III ATD at Ford, 3) dual-recliner ABTS in a 48 km/h (30 mph) test with a 95th Hybrid III ATD leaning inboard at CAPE and 4) dual-recliner ABTS and Escape in 40 km/h (25 mph) in-position and out-of-position tests with a 50th Hybrid III ATD at Ford. The sled tests showed that single-recliner ABTS seats twist in severe rear impacts with the pivot side deformed more rearward than the stanchion side. The use of dual recliners on ABTS seats prevented twist but increased the stiffness causing serious
Viano, David, Burnett, Roger, White, Samuel, Stephens, Gregory, Parenteau, Chantal
The Role of Seat Belt Restraint System Components in Rear-End Collisions2021-01-091204/06/2021
The role of seatback strength on occupant motion during rear-end collisions has been a focus of scientific investigation for decades. Despite being an integral component of the occupant restraint system, the role of seat belt restraints and the potential effect of various seat belt restraint system components, like pretensioners and latch plate design, on occupant motion and injury potential during rear-end collisions has received less attention. This study identifies and highlights what is currently understood about the role of seat belt restraints and components in rear-end collisions from the existing literature in detail for the first time. Previous studies that have investigated the role of pretensioning in occupant motion and loading did not provide detailed assessments of pretensioning effects on webbing loads and displacement, nor did they discuss the relationship between pretensioner deployment and latch plate design. Static pretensioner deployment tests were conducted to
Toney-Bolger, Megan, Croteau, Jeffrey, Dibb, Alan, Weber, Paul, Stankewich, Charles, Van Arsdell, William
Seat Performance in Rear Impacts: Seatback Deflection and Energy Dissipation2021-01-091604/06/2021
Occupant protection in rear crashes is complex. While seatbelts and head restraints are effective in rear impacts, seatbacks offer the primary restraint component to front-seat occupants in rear impacts. Seatback deflection due to occupant loading can occur in a previous rear crash and/or in multiple-rear event crashes. Seatback deflection will in-turn affect the plastic seatback deformation and energy absorption capabilities of the seat. This study was conducted to provide information on seatback deflection and seat energy consumption in low and high-speed rear impacts. The results can be used to examine seatback deflection and energy consumed in a previous rear impact, or in collisions with multiple rear impacts. Prior seatback deflection and energy absorption can affect the total remaining energy absorption and seat performance for a subsequent rear impact. Rear sled tests included eight 16 km/h tests conducted with the BioRID and eight matched 40 km/h tests with the 50th percentile
White, Samuel, Parenteau, Chantal, Burnett, Roger
Effect of Occupant Weight and Initial Position in Low-to-High Speed Rear Sled Tests with Older and Modern Seats2021-01-091804/06/2021
The average body weight of the US population has increased over time. This study investigates the effect of increasing weight on seat and occupant responses in 15-18 km/h and 42 km/h rear sled tests. The effect of initial occupant posture is also discussed. Seven tests were conducted with lap-shoulder belted ATDs (anthropometric test device) placed on older and modern driver seats. Four tests were conducted with a 50th percentile male Hybrid III, two with 95th percentile male Hybrid III and one with a BioRID. The ATDs were ballasted to represent a Class I or II obese occupant in three tests. The tests were matched by seat model and sled velocity. The effect of occupant weight was assessed in three matches. The results indicated an increase in seatback deflection with increasing occupant weight. For example, the average dynamic deflection was 2.8-times greater with a ballasted 95th ATD than with a 50th ATD (20.2 v 7.3 degree) in the 15-18 km/h sled tests and 1.4-times greater with a
Parenteau, Chantal, Burnett, Roger, Viano, David, White, Samuel
Drivers’ Responses to Lead Vehicles: Thresholds for Triggering an Emergency Response, Age Differences, Crash Risks, and Influence of Secondary Task Engagement2021-01-089804/06/2021
Analyses of driver response time studies and fatal crash statistics were examined to determine: 1. whether all rear-end crash types can be analyzed as one crash type, 2. average braking thresholds for drivers, and 3. the influence cell phone usage has on drivers’ response times when responding to a lead vehicle. The goal of this research is to recommend protocols for investigating LV crashes that is supported by the literature. Two distinct lead vehicle [LV] response time events emerged: LV platoon (two vehicles traveling together in close proximity) and LV looming (a vehicle approaching a stopped or much slower LV). In normal driving, platoon LV events were very common but resulted in very few crashes per exposure. Young drivers were over-represented when they did occur. Onset of the hazardous event was when the LV decelerated, and drivers began braking roughly 3 to 5 seconds before impact. These results were consistent with the braking thresholds by naturalistic drivers in congested
Muttart, Jeffrey, Dinakar, Swaroop, Edewaard, Darlene
Effect of Seat Back Restriction on Head, Neck and Torso Responses of Front Seat Occupants When Subjected to a Moderate Speed Rear-Impact2021-01-092004/06/2021
During high-speed rear impacts with delta-V > 25 km/h, the front seats may rotate rearward due to occupant and seat momentum change leading to possibly large seat deflection. One possible way of limiting this may be by introducing a structure that would restrict large rotations or deformations, however, such a structure would change the front seat occupant kinematics and kinetics. The goal of this study was to understand the influence of seat back restriction on head, neck and torso responses of front seat occupants when subjected to a moderate speed rear-impact. This was done by simulating a rear impact scenario with a delta-V of 37.4 km/h using LS-Dyna, with the GHBMC M50 occupant model and a manufacturer provided seat model. The study included two parts, the first part was to identify worst case scenarios using the simplified GHBMC M50-OS, and the second part was to further investigate the identified scenarios using the detailed GHBMC M50-O. The baseline condition included running
Ramachandra, Rakshit, Pradhan, Vikram, Kang, Yun Seok, Davidson, Russell, Humer, Mladen, Zhang, Jianmin
Tesla casts a new strategy for lightweight structures20AUTP06_0106/01/2020
The EV maker boldly invests in the world's largest aluminum die-casting machine to manufacture entire rear underbody structures. Aluminum is synonymous with “weight-saving” in most contemporary automotive-engineering reference points. But apart from a few applications - most notably Ford's F-Series pickups - aluminum largely is deployed where steel can be readily displaced without performance loss or for comparatively small components that deliver comparatively small weight or process savings. Electric-vehicle maker Tesla is readying the next step in aluminum use, however - one that effectively matches Ford's “big gain” approach by specifying a massive piece of structural die-cast aluminum for the rear underbody of the recently launched Model Y crossover. According to Tesla CEO Elon Musk, this new aluminum application represents a radical step for its design and manufacturing advantages and its light-weighting potential. Musk is renowned for outsized promises, but in the case of the
Visnic, Bill
The Effect of Changing Vehicle Seat Stiffness: A MADYMO Sensitivity Analysis2020-01-052404/14/2020
In low-speed, rear-end collisions, the occupant in the target vehicle moves rearward relative to the vehicle and interacts with the seatback and seat bottom. Due to the direct interaction of the occupant with the seat, seat stiffness can affect the kinematics of the occupant. Generic seat stiffness values are often used as input parameters in computer programs, such as MADYMO, that are used to model low-speed, rear-end collisions and simulate occupant kinematics. To create an accident specific simulation, the model could take into account all aspects of the accident including the person involved, the subject vehicle, and the subject vehicle seat. Recent research has demonstrated that the seat stiffness of the compressible structure of the seat, comprised of foam and springs, can vary between vehicles, and also can vary between regions within a single vehicle seat. In order to examine the influence of seat stiffness on occupant kinematics and internal loads, MADYMO simulations were
Cruise, Denise R., Suderman, Bethany L., Yang, Nicholas H., Stepan, Lenka, Scher, Irving S.
Methods for Quantifying the Impact Severity of Low-Speed Side Impacts at Varying Angles2020-01-064104/14/2020
Accurately quantifying the severity of minor vehicle-to-vehicle impacts has commonly been achieved by utilizing the Momentum Energy Restitution (MER) method. A review of the scientific literature revealed investigations assessing the efficacy of the MER method primarily for: 1) inline rear-end impacts, 2) offset rear-end impacts, and 3) side impacts configured with the bullet vehicle striking the target vehicle at an approximate 90° angle. To date, the utility of the MER method has not been thoroughly examined and readily published for quantifying oblique side impacts. The aim of the current study was to analyze the effectiveness of the MER method for predicting the severity of side impacts at varying angles. Data were collected over a series of 12 tests with bullet-to-target-vehicle contact angles ranging from approximately 45° to 315° with corresponding impact speeds of approximately 12.5 km/h (7.8 mph) to 16.1 km/h (10.0 mph). Vehicle damage profiles were documented after each test
Brink, Justin, Swinford, Scott, Furbish, Christopher, Jones, Brian, Welcher, Judson, Anderson, Robert
The Effect of FMVSS 301R on Vehicle Structure in Rear Impact2020-01-122604/14/2020
Vehicle structures are designed to manage impact forces and transfer crash energy, in addition to their primary purpose of connecting all the vehicle powertrain, suspension, steering, HVAC, electronics, occupant accommodation, and weatherproofing. With the introduction of new rear impact requirements, the design of rear structures has evolved and the use of high strength steel has increased. This study objective was to assess the effect of new FMVSS 301 requirements on vehicle responses. NHTSA conducted 33 offset rear crash tests at 80 km/h with vehicles that pre-dated the newer FMVSS 301R requirements and 88 with vehicles that complied with the newer requirements, with a 2009-2015 model year range. The vehicles were grouped by size and the permanent crush was tabulated. Overall, the struck-side maximum crush decreased in the newer model vehicles. Seven matches with pre and post 301R were identified on the same make and model vehicle of different generations. The matched tests were
Parenteau, Chantal, Stephens, Gregory, Yaek, Jennifer, Gregory, Serge
Occupant Dynamics during Moderate-to-High Speed Rear-End Collisions2020-01-051604/14/2020
Numerous studies have evaluated occupant kinematics and dynamics in “low-speed” rear-end impacts (delta-V ≤ 8 mph). Occupant biomechanics during “moderate-to-high” speed rear impacts (9 ≤ delta-V ≤ 20 mph) has not been thoroughly examined. This study characterized the motions and forces experienced by the head, neck, torso, hip, and left/right femur during these collisions. The publicly available NHTSA rear-end crash test data were examined. More specifically, the FMVSS 301 Fuel System Integrity tests were used. The test procedure involved a 30 mph moving barrier impacting the rear of the vehicles. Instrumented 50th-percentile male (N = 47) or 5th-percentile female (N = 4) Hybrid III ATDs were positioned in the driver seat. Occupant data including head accelerations, upper/lower neck shear and axial forces, upper/lower neck moments, lower neck acceleration, torso accelerations, torso deflection, hip accelerations, and left/right femur axial forces were evaluated and compared to
Atarod, Mohammad
The Effect of Crash Severity and Structural Intrusion on ATD Responses in Rear-End Crashes2020-01-122404/14/2020
This study assesses vehicle and occupant responses in six vehicle-to-vehicle high-speed rear impact crash tests conducted at the Exponent Test and Engineering Center. The struck vehicle delta Vs ranged from 32 to 76 km/h and the vehicle centerline offsets varied from 5.7 to 114 cm. Five of the six tests were conducted with Hybrid III ATDs (Anthropometric Test Device) with two tests using the 50th male belted in the driver seat, one test with an unbelted 50th male in the driver seat, one test with a 95th male belted in the driver seat, and one with the 5th female lap belted in the left rear seat. All tests included vehicle instrumentation and three tests included ATD instrumentation. The ATD responses were analyzed and compared to corresponding IARVs (injury assessment reference values). Ground-based and onboard vehicle videos were synchronized with the vehicle kinematic data and biomechanical responses. The timing of the vehicle crush, occupant compartment intrusion, seatback motion
Parenteau, Chantal, Croteau, Jeffrey, Zolock, John
Low-Energy Seat Compression: Characterizing Stiffness in Different Vehicles2020-01-052704/14/2020
In rear-end collisions, occupants move rearward relative to the vehicle interior, while compressing the seatback. In low-energy impacts, the stiffness of the non-frame seat components may influence the kinematic response of an occupant. Previous research has reported seat stiffness from experiments for a limited number of seats. Because passenger vehicle seats have evolved, this current work reports a range of seat stiffnesses for modern passenger vehicles. A portable measuring device to characterize vehicle seat stiffness was built to accommodate a wide range of vehicle types. The device measured simultaneously the force applied to the seat and the displacement of the seat cushion. Seats of sedans, crossovers, sport utility vehicles, minivans, and pickup trucks for model years between 2016 and 2020 were tested using the device. For each seat, three measurements were taken for four different seat regions: upper seatback, lower seatback, aft seat bottom and fore seat bottom. The seat
Suderman, Bethany L., Cruise, Denise R., Yang, Nicholas H., Lau, Edmund, Stepan, Lenka, Scher, Irving
Update on Second-Row Children Responses in Rear and Frontal Crashes with a Focus on the Potential Effect of Stiffening Front Seat Structures2020-01-121504/14/2020
NHTSA has recently been petitioned to address the protection of second-row children in rear crashes due front seatback performance. The protection of children is important. However, it is more complex than assessing front seat performance in rear impacts. Viano, Parenteau (2008 [1]) analyzed cases of serious-to-fatally injured (MAIS 3+F) children up to 7 years old in the second row in rear impacts involving 1990+ model year vehicles using 1997-2005 NASS-CDS. They observed that intrusion was an important factor pushing the child forward into the back of the front seat, B-pillar or other front structure. To help assess whether stiffening the front seats would be beneficial for second-row child safety, the 2008 study was updated using more recent data and model year vehicles. In the present study, 1997-2015 NASS-CDS data were analyzed for serious-to-fatally (MAIS 3+F) injured 0- to 7-year old children in the second row with 1994+ model year vehicles. First, the data were analyzed to
Parenteau, Chantal, Viano, David
Head and Neck Loading Conditions over a Decade of IIHS Rear Impact Seat Testing2019-01-122704/02/2019
Rear-end impacts are the most common crash scenario in the United States. Although automated vehicle (AV) technologies, such as frontal crash warning (FCW) and automatic emergency braking (AEB), are mitigating and preventing rear-end impacts, the technology is only gradually being introduced and currently has only limited effectiveness. Accordingly, there is a need to evaluate the current state of passive safety technologies, including the performance of seatbacks and head restraints. The objective of this study was to examine trends in head and neck loading during rear impact testing in new vehicle models over the prior decade. Data from 601 simulated rear impact sled tests (model years 2004 to 2018) conducted as a part of the Insurance Institute for Highway Safety (IIHS) Vehicle Seat/Head Restraint Evaluation Protocol were obtained. This dynamic evaluation involves a simulated rear-end crash using a Biofidelic Rear Impact (BioRID IIg) ATD positioned in the seat attached to a crash
Scanlon, John M., Isaacs, Jessica, Garman, Christina
Seat Performance and Occupant Moving Out of the Shoulder Belt in ABTS (All-Belts-to-Seat) in Rear Impacts2019-01-103104/02/2019
This study examined occupant and seat responses with ABTS (all-belts-to-seat) in rear end collisions. Some have claimed improved ABTS seat performance and retention in rear impacts than conventional seats. ABTS seats tend to have higher ultimate yield strengths than conventional yielding seats. Most ABTS seats have asymmetric seatback stiffness due to the need for additional structure on one side of the seat to support shoulder belt loads. Many designs use a single-side recliner and single stanchion that anchors the D-ring. This asymmetry results in twisting of the seatback in severe rear impacts. Seatback twist can allow the occupant to move away from the shoulder belt. Rearward pull tests on ABTS seats also demonstrates seatback twisting and in some cases large drops in load during the test. The added strength and stiffness of ABTS seats lead to designs that are vulnerable to sudden force drops from separated parts.
White, Samuel, Viano, David, Burnett, Roger
Lateral and Tangential Accelerations of Left Turning Vehicles from Naturalistic Observations2019-01-042104/02/2019
When reconstructing collisions involving left turning vehicles at intersections, accident reconstructionists are often required to determine the relative timing and spacing between two vehicles involved in such a collision. This time-space analysis frequently involves determining or prescribing a path and acceleration profile for the left turning vehicle. Although numerous studies have examined the straight-line acceleration of vehicles, only two studies have presented the tangential and lateral acceleration of left turning vehicles. This paper expands on the results of those limited studies and presents a methodology to automatically detect and track vehicles in a video file. The authors made observations of left turning vehicles at three intersections. Each intersection incorporated permissive green turn phases for left turning vehicles. The authors recorded video of left turning vehicles at each intersection from a small unmanned aerial system (sUAS), and that video was analyzed
Carter, Neal, Beier, Steven, Cordero, Rheana
Low Speed Override of Passenger Vehicles with Heavy Trucks2019-01-043004/02/2019
In low speed collisions (under 15 mph) that involve a heavy truck impacting the rear of a passenger vehicle, it is likely that the front bumper of the heavy truck will override the rear bumper beam of the passenger vehicle, creating an override/underride impact configuration. There is limited data available for study when attempting to quantify vehicle damage and crash dynamics in low-speed override/underride impacts. Low speed impact tests were conducted to provide new data for passenger vehicle dynamics and damage assessment for low speed override/underride rear impacts to passenger vehicles. Three tests were conducted, with a tractor-trailer impacting three different passenger vehicles at 5 mph and 10 mph. This paper presents data from these three tests in order to expand the available data set for low speed override/underride collisions.
Danaher, David, Neale, William, McDonough, Sean, Donaldson, Drew
Driver Risk Perception Model under Critical Cut-In Scenarios2018-01-162608/07/2018
In China Cut-in scenarios are quite common on both highway and urban road with heavy traffic. They have a potential risk of rear-end collision. When facing a cutting in vehicle, driver tends to brake in most case to reduce collision risk. The timing and dynamic characteristics of brake maneuver are indicators of driver subjective risk perception. Time to collision (TTC) and Time Headway (THW) demonstrate objective risk. This paper aims at building a model quantitatively revealing the relationship between drivers’ subjective risk perception and objective risk. A total of 66 valid critical Cut-in cases was extracted from China-FOT, which has a travel distance of about 130 thousand miles. It is found that under Cut-in scenarios, driver tended to brake when the cutting in vehicle right crossing line. This time point was defined as initial brake time. Brake strength and brake speed were taken to describe brake maneuver. Average brake pressure (ABP) and acceleration at initial brake time
Ma, Xuehan, Feng, Zhiwei, Zhu, Xichan, Ma, Zhixiong
2021-12-29.TEST Design and Implementation of Adaptive Range LIDAR System (ARLS) for Autonomous Braking Assistance at High Speeds in Automobiles2018-01-004004/03/2018
Autonomous braking systems are prevalent in mid/upper-mid range vehicles today. The major drawback: acute boundary condition during which the system will function. The paper describes the implementation of Adaptive Range LIDAR Systems (ARLS) containing a state of the art collimator and wave shaper with a 140̊ sweep MEMS mirror, capable of calculating beam convergence as a function of distance, considering multiple obstacles ahead of it. The paper also describes the use of ARLS for ACC (Adaptive Cruise Control) and Autonomous braking, reinforcing the available software structure with more data points. Contrary to the other systems that detect objects/obstacles from a stationary point of reference, ARLS determines the velocity of obstacle with respect to the ground point of reference and computes most optimum brake effort curve. The brake curves are alike for every situation, as it is dynamic in nature, hence, additional electronics ensure physical curve tracing by manipulating the
Mishra, Jainendra
Plug-in hybrid brings Honda into sharper Clarity18AUTP02_0802/01/2018
Honda's recently introduced Clarity plug-in hybrid sedan is the third variant of this revitalized and electrified nameplate. It joins the Clarity Fuel Cell, which debuted in December 2016 and the Clarity Battery Electric that arrived in the U.S. market in August 2017. The Plug-in Hybrid is the only one that's available in all 50 states and the sole version customers can purchase. The base Plug-in is $33,400 with a more upscale Touring model offering features like leather seats and satellite navigation ringing in at $36,600. Available by lease only, the Fuel Cell is just for California consumption and the Battery Electric version is currently offered only in a couple U.S. West Coast states at present. Honda will also offer the Plug-in in Canada.
Sessions, Ron
Accuracy of the Momentum Energy Restitution Method for Offset Inline Minor Rear-End Impacts2017-01-142503/28/2017
In minor inline rear-end accidents, vehicle damage is the primary tangible indicator of impact severity or vehicle change in velocity (ΔV). A technique for calculating change in velocity based on vehicle damage for collinear impacts involves application of the Momentum Energy Restitution (MER) method. Offset inline minor rear-end impact testing, wherein minimal vehicle bumper or contact surface engagement occurs, has not been readily published to date. Thus, instrumented offset inline rear-end impacts were performed utilizing a 1997 Ford F-150 Pickup, 1996 Kia Sephia, and 1995 Chrysler LeBaron GTC to determine if the MER method can accurately calculate a vehicle’s ΔV when collinear contact does not occur. Vehicle engagement involved 5.1 cm to 76.2 cm of overlap with impact speeds ranging between 0.7 m/s and 4 m/s. Test results indicated that a 15.2 cm or less overlap between vehicle impacting surfaces promoted sideswipe impacts or an incomplete transfer of momentum relative to the
Jones, Brian, Calabro, Michael, Brink, Justin, Swinford, Scott
Vehicle Rear Impacts and Spinal Disc Herniations in Occupants: Is there a Basis for Causation?2017-01-145803/28/2017
Disc herniations in the spine are commonly associated with degenerative changes, and the prevalence increases with increasing age. With increasing number of older people on U.S. roads, we can expect an increase in clinical findings of disc herniations in occupants involved in rear impacts. Whether these findings suggest a causal relationship is the subject of this study. We examined the reported occurrence of all spine injuries in the National Automotive Sampling System - Crashworthiness Data System (NASS-CDS) database from 1993 to 2014. There were over 4,000 occupants that fit the inclusion criteria. The findings in this study showed that, in the weighted data of 2.9 million occupants, the most common spine injury is an acute muscle strain of the neck, followed by strain of the low back. The delta-V of a rear impact is a reliable indicator of the rate of acute cervical strain in occupants exposed to such impacts. The number of disc herniations was small in all three segments of the
Lam, Tack, Ivarsson, B. Johan
Collision Deformation ClassificationJ224_201702 (Historical)02/23/2017
The purpose and scope of this SAE Recommended Practice is to provide a basis for classification of the extent of vehicle deformation caused by vehicle accidents on the highway. It is necessary to classify collision contact deformation (as opposed to induced deformation) so that the accident deformation may be segregated into rather narrow limits. Studies of collision deformation can then be performed on one or many data banks with assurance that the data under study are of essentially the same type.1 The seven-character code is also an expression useful to persons engaged in automobile safety, to describe appropriately a field-damaged vehicle with conciseness in their oral and written communications. Although this classification system was established primarily for use by professional teams investigating accidents in depth, other groups may also find it useful. The classification system consists of seven characters, three numeric, and four alphameric, arranged in a specific order. The
Data Collection and Archiving Standards Committee
Accident Scenarios on Indian Roads: A Study of Driver Behaviour and Road Infrastructure, based on data collected by ADAC2017-26-000201/10/2017
Most of the time in motor vehicle accidents, the driver of the vehicle (especially driver of the larger vehicle in case of collision involving multiple vehicles) is held responsible for rash and negligent driving. But in-depth study and statistics, points out several external or environmental factors playing crucial role in these unfortunate incidents. In some cases these factors directly influence an accident/crash and in some cases these factors influence the behavior pattern of the driver, which increases risk of unsafe practices. Based on the real time data collected by ADAC on the Gurgaon - Jaipur Stretch of NH-8 and others parts of India, some of the factors that directly or indirectly influences the drivers behaviour, are illustrated in this paper.
Padhy, Sitikantha, Agrawal, Pradeep, Yadav, Yoginder
Ambulance Litter Integrity, Retention, and Patient RestraintJ3027_201611 (Historical)11/01/2016
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
Occupant Restraint and Equipment Mounting Integrity - Rear Impact Ambulance Patient CompartmentJ3044_201608 (Historical)08/17/2016
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
Comparison of the Accuracy and Sensitivity of Generation 1, 2 and 3 Toyota Event Data Recorders in Low-Speed Collisions2016-01-149404/05/2016
The accuracy of the speed change reported by Generation 1 Toyota Corolla Event Data Recorders (EDR) in low-speed front and rear-end collisions has previously been studied. It was found that the EDRs underestimated speed change in frontal collisions and overestimated speed change in rear-end collisions. The source of the uncertainty was modeled using a threshold acceleration and bias model. This study compares the response of Generation 1, 2 and 3 Toyota EDRs from Toyota Corolla, Camry and Prius models. 19 Toyota airbag control modules (ACMs) were mounted on a linear sled. The ACMs underwent a series of frontal and rear-end haversine crash pulses of varying severity, duration and peak acceleration. The accuracy and trigger thresholds of the different models and generations of EDRs were compared. There were different accuracy trends found between the early Generation 1 and the more modern Generation 2 and 3 EDRs. There were also differences found in the threshold and trigger
Xing, Peter, Lee, Felix, Flynn, Thomas, Wilkinson, Craig, Siegmund, Gunter
Crashworthiness Design of Automotive Body in White using Topology Optimization2016-01-153504/05/2016
Based on equivalent static loads method (ESL), a nonlinear dynamic topology optimization is carried out to optimize an automotive body in white (BIW) subjected to representative legislative crash loads, including frontal impact, side barrier impact, roof crush and rear impact. To meet the crashworthiness performances, two evaluation indexes are defined to convert the practical engineering problems into mathematic optimization problems. The strain energy is treated as the stiffness evaluation index of the BIW and the relative displacement is employed as the compliance index of the components and parts. The optimization problem could be changed into maximizing structural stiffness of the design space while constraining the relative displacements of the passenger cabin lower than a certain value to guarantee the stiffness of passenger cabin, constraining the relative displacements of the front and rear cabin greater than a certain value to increase the energy absorption during the crash
Tian, Linli, Gao, Yunkai
Study on TTC Distribution when Approaching a Lead Vehicle2016-01-145204/05/2016
In order to help avoid or mitigate rear-end collisions a Pre-Collision System (PCS) was developed. The purpose of this study is to clarify the Time-to-Collision (TTC) distribution when approaching a lead vehicle under normal driving condition. To enhance the effectiveness of PCS, warnings and/or automatic brake activation should happen as early as possible, however, if too early there is a high possibility of false warnings or activations, which is not desirable. If the distribution of distance to a lead vehicle under normal driving conditions is quantified, an approach limit can be estimated. In this study, we try to clarify a TTC distribution that is approximated by a log-normal distribution. Then, we investigate the Enhanced Time-to-Collision (ETTC) that is the secondary predictive value of TTC. And, we clarify the log-normal distribution of ETTC is a more stable approximator of normal driving than a log-normal distribution of TTC.
Murata, Eiichiro, Usui, Tasuku, Nogi, Kazunori, Takahashi, Hiroyuki
Vertical Occupant Loading in Car Crashes; Test Methods and Countermeasures2015-01-145904/14/2015
Vertical loading can cause thoracic and lumbar spine injuries to a car occupant. Crashes potentially causing occupant vertical loads include; rollover events or free flying events when the car lands on its wheels, and run off road events when the car goes into the ditch and collides with an embankment. To date, there is no standardized test method evaluating this occupant loading mechanism. The aim of this study was to develop test methods addressing vertical occupant loading for car occupants and to evaluate countermeasures for reduction of such loads. Based on real world run off road crashes, representative test track methods were developed. These complete vehicle test track methods were used to provide input to a simplified and repeatable rig test method. The rig test method comprises a dummy positioned in a seat attached to a frame and exposed to a vertical acceleration. Vertical pelvis acceleration is monitored, as an indication of potential loads through the spine. Two different
Jakobsson, Lotta, Björklund, Magnus, Axelson, Anders
Driver Perceived Threat and Behavior in Rear End Collision Avoidance Situations2015-01-141404/14/2015
The focus of this paper is the threat assessment of perceived threat by drivers in collision avoidance situations. The understanding of the decision making process with regards to the initiation of a driver intervention is a crucial step to gain insight into driver's steering and braking behavior in case of an imminent threat (rear-end collision). Hence a study with various test subjects and a test vehicle has been conducted. The study has helped to understand how drivers behave in potential rear-end collision situations arising from the traffic situation (e.g. start of a traffic jam). This information is of major importance for designing autonomous collision avoidance systems and an important step towards autonomous driving. Autonomous driving in vehicles require system interventions to be initiated as early and safely as possible in order to avoid the collision and to avoid unstable vehicle dynamics situations. In parallel, collision avoidance maneuvers need to be balanced between
Shah, Jitendra, Benmimoun, Mohamed
Occupant Restraint and Equipment Mounting Integrity - Rear Impact System-Level Ambulance Patient CompartmentJ3044_201406 (Historical)06/25/2014
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
New Trial Analysis of Characteristics of Accidents and Traffic Violations by Elderly Drivers in Japan2014-01-912705/09/2014
The number of elderly drivers is increasing in Japan and ensuring the safety of elderly drivers is becoming an important issue. The authors previously conducted an analysis of the characteristics of accidents and traffic violations by elderly drivers based on the number of accidents in which they were rear-ended. This method was used in order to exclude the influence of driving frequency. As a result of that analysis, it was found that the likelihood of violations committed by elderly drivers was not particularly higher than in other age groups, while the likelihood of accidents caused by them was higher. The risk of causing an accident was judged to be about two times higher in elderly drivers than in the 35-44 year age group. However, the methodology presupposed that collisions in which a driver is rear-ended are accidents that occur randomly, and that they occur with the same probability in each age group. To verify the results of that study, we attempted a new analytical method
Morita, Kazumoto, Sekine, Michiaki
The Psychological and Accident Reconstruction “Thresholds” of Drivers' Detection of Relative Velocity2014-01-043704/01/2014
Relative velocity detection thresholds of drivers are one factor that determines their ability to avoid rear-end crashes. Laboratory, simulator and driving studies show that drivers could scale relative velocity when it exceeded the threshold of about 0.003 rad/sec. Studies using accident reconstruction have suggested that the threshold may be about ten times larger. This paper discusses this divergence and suggests reasons for it and concludes that the lower value should be used as a true measure of the psychological threshold for detection of relative velocity.
Mortimer, Rudolf, Hoffmann, Errol, Kiefer, Aaron
A Study on Modeling of Driver's Braking Action to Avoid Rear-End Collision with Time Delay Neural Network2014-01-020104/01/2014
Collision avoidance systems for rear-end collisions have been researched and developed. It is necessary to activate collision warnings and automatic braking systems with appropriate timing determined by a monitoring system of a driver's braking action. Although there are various systems to monitor driving behavior, this study aims to create a monitoring system using a driver model. This study was intended to construct a model of a driver's braking action with the Time Delay Neural Network (TDNN). An experimental scenario focuses on rear-end collisions on a highway, such as the driver of a host vehicle controlling the brake to avoid a collision into a leading vehicle in a stationary condition caused by a traffic jam. In order to examine the accuracy of the TDNN model, this study used four parameters: the number of learning, the number of neurons in the hidden layer, the sampling time with 0.01 second as a minimum value, and the number of the delay time. In addition, this study made a
Hirose, Toshiya, Gokan, Masato, Kasuga, Nobuyo, Sawada, Toichi
Standard No. 125; Warning devices.TITLE49-SEC571-125-201310/01/2013
S1. Scope. This standard establishes requirements for devices, without self-contained energy sources, that are designed to be carried in motor vehicles and used to warn approaching traffic of the presence of a stopped vehicle, except for devices designed to be permanently affixed to the vehicle. S2. Purpose. The purpose of this standard is to reduce deaths and injuries due to rear end collisions between moving traffic and disabled vehicles. S3. Application. This standard applies to devices, without self-contained energy sources, that are designed to be carried in buses and trucks that have a gross vehicle weight rating (GVWR) greater than 10,000 pounds. These devices are used to warn approaching traffic of the presence of a stopped vehicle, except for devices designed to be permanently affixed to the vehicle. S4. Definitions. Entrance angle means the angle having as its sides the line through the center, and normal to the face, of the object to be tested, and the line from the center
Impact of Driver's Steer Control on Truck-Trailer Combination when Negotiating NATO Double Lane Change Maneuver2013-01-040404/08/2013
In this study, a closed-loop driver-truck-trailer system model is established with ADAMS/Car. A double lane change maneuver (DLCM) path boundary is set up based on the NATO AVTP 03-160W requirement. The best driver preview path at a given speed to pass the DLCM is derived from optimization of the closed-loop driver-vehicle-road system, where the objective is to successfully pass the DLCM at the given forward speed. This must be done without violating the maneuver boundary, lifting any tires off the ground, as well as staying within the Driver's steering effort limit. Depending upon the Driver's control strategy, which is reflected by the formulation of the optimal objective, the dynamic responses of the truck-trailer combination will vary. Two extreme conditions are discussed in this study: full and no consideration of trailer, respectively, when negotiating the DLCM. The vehicle responses and Driver's preview paths under these two conditions are further compared to demonstrate the
Yang, Xiaobo
Using Data from a DriveCam Event Recorder to Reconstruct a Vehicle-to-Vehicle Impact2013-01-077804/08/2013
This paper reports a method for analyzing data from a DriveCam unit to determine impact speeds and velocity changes in vehicle-to-vehicle impacts. A DriveCam unit is an aftermarket, in-vehicle, event-triggered video and data recorder. When the unit senses accelerations over a preset threshold, an event is triggered and the unit records video from two camera views, accelerations along three directions, and the vehicle speed with a GPS sensor. In conducting the research reported in this paper, the authors ran four front-to-rear crash tests with two DriveCam equipped vehicles. For each test, the front of the bullet vehicle impacted the rear of the stationary target vehicle. Each of the test vehicles was impacted in the rear twice - once at a speed of around 10 mph and again at a speed around 25 mph. The accuracy of the DriveCam acceleration data was assessed by comparing it to the data from other in-vehicle instrumentation. We found that, for in-line front-to-rear crashes like those
Rose, Nathan A., Carter, Neal R., Pentecost, David, Bortles, William, Voitel, Tilo
Lumbar Spine Injuries in Rear Impacts of Different Severities2013-01-022104/08/2013
Volunteer subject studies in low-speed rear impacts have shown that significant lumbar spine injuries are unlikely in such collisions. Anthropomorphic test devices (ATD) used in low to medium speed rear impact simulations have similarly revealed an unlikely mechanism to cause lumbar spine injuries. However, low back complaints after rear impacts are common in clinical practice. We attempt here to determine the incidence of lumbar spine injuries from actual field data which may provide an insight into the apparent paradox between experimental data and clinical practice. We examined the incidence of all spine injuries in the NASSCDS (National Automotive Sampling System - Crashworthiness Data System) database from 1993 to 2009. We limited the data to only look at rear-end crashes involving two vehicles. We analyzed crash severity (delta-V), occupant injuries by AIS (Abbreviated Injury Scale) code, seat performance and restraint use in over 7,500 (with a weighted value of 2.5 million
Yang, Nicholas, Lam, Tack, Dainty, David, Lau, Edmund
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