Browse Topic: Rear-end crashes

Items (239)

Feasibility of Road Longitudinal Profiles for Automated Vehicles Based on Vehicle Dynamics

2025-01-715003/19/2025

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 Impacts

2024-26-000301/16/2024

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 Rear

2024-26-000501/16/2024

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

Development of a Variable Stiffness Seatback

2022-01-103703/29/2022

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

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

Validation of Utilizing a Self-Propelled Crash Sled to Simulate Occupant Accelerations in Minor Rear-End Impacts

2022-01-104003/29/2022

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

Assessment of the 50th Hybrid III Responses in Blunt Rear Impacts to the Torso

2021-01-091904/06/2021

Blunt impacts to the back of the torso can occur in vehicle crashes due to interaction with unrestrained occupants, or cargo in frontal crashes, or intrusion in rear crashes, for example. Six pendulum tests were conducted on the back of an instrumented 50th percentile male Hybrid III ATD (Anthropomorphic Test Device) to determine kinematic and biomechanical responses. The impact locations were centered with the top of a 15-cm diameter impactor at the T1 or at T6 level of the thoracic spine. The impact speed varied from 16 to 24 km/h. Two 24 km/h tests were conducted at the T1 level and showed repeatability of setup and ATD responses. The 16 and 24 km/h tests at T1 and T6 were compared. Results indicated greater head rotation, neck extension moments and neck shear forces at T1 level impacts. For example, lower neck extension was 2.6 times and 3.8 times greater at T1 versus T6 impacts at 16 and 24 km/h, respectively. A 24 km/h test at T1 was also conducted with a seatback attached to the

Buckman, Jennifer L., Parenteau, Chantal S., Burnett, Roger, Viano, David C., Andrecovich, Christopher

Tesla casts a new strategy for lightweight structures

20AUTP06_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

Methods for quantifying the impact severity of low-speed side impacts at varying angles

2020-01-064104/14/2020

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 examined and readily published for quantifying oblique side impacts. The aim of the current study was to observe the effectiveness of the MER method for predicting the severity of side impacts at varying angles. Data were collected over a sequence of 12 tests with bullet-to-target-vehicle contact angles ranging from approximately 45° to 135° with corresponding impact speeds of approximately 13.7 km/h to 16.4 km/h. Vehicle damage profiles documented after each test allowed for the application of the

Brink, Justin, Swinford, Scott, Furbish, Christopher, Jones, Brian, Welcher, Judson, Anderson, Robert

The Effect of FMVSS 301R on Vehicle Structure in Rear Impact

2020-01-122604/14/2020

Vehicle structures are designed to manage impact forces and transfer crash energy. 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 86 with vehicles that complied with the newer requirements, with a 2009-2015 model year range. The vehicles were grouped by size and the crush was tabulated. Overall, the struck-side maximum crush decreased in the newer model vehicles. Seven matches with pre and post 301R were identified based on make and model. The matched tests were reconstructed using video analysis and crush measurements of both the barrier and vehicle. Generalized vehicle stiffness was determined for each of the matched tests and indicated that vehicles generally became

Parenteau, Chantal, Stephens, Gregory, Yaek, Jennifer, Gregory, Serge

Update on Second-Row Children Responses in Rear and Frontal Crashes with a Focus on the Potential Effect of Stiffening Front Seat Structures

2020-01-121504/14/2020

The protection of children in rear seats is an important issue, but it is a more complex than assessing front seat performance in rear impacts. 1997–2015 NASS-CDS data were analyzed to estimate the distribution and risk of seriously-to-fatally (MAIS 3+F) injured 0-7 year old children in the 2nd row by crash types with 1994+ model year vehicles. The results showed that children were frequently injured in frontal (39.3%) and in side (27.2%) crashes. The injury risk was highest in rollover (1.72% ± 0.36) followed by rear crashes (0.75% ± 0.56%). Individual rear and frontal impact cases were also reviewed to better understand injury mechanisms of children in the 2nd row. The cases were downloaded and reviewed. There were 15 injured children involved in 14 rear impact crashes. Half were associated with significant intrusion (12+ inches) intrusion of their seating area, pushing the child forward. More than half (7 out of 11 cases with known information) of the front seatbacks remained in

Parenteau, Chantal, Viano, David

Seat Performance and Occupant Moving Out of the Shoulder Belt in ABTS (All-Belts-to-Seat) in Rear Impacts

2019-01-103104/02/2019

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 Observations

2019-01-042104/02/2019

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

Driver Risk Perception Model under Critical Cut-In Scenarios

2018-01-162608/07/2018

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 Automobiles

2018-01-004004/03/2018

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 Clarity

18AUTP02_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

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

Accuracy of the Momentum Energy Restitution Method for Offset Inline Minor Rear-End Impacts

2017-01-142503/28/2017

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

Collision Deformation Classification

J224_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 ADAC

2017-26-000201/10/2017

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 Restraint

J3027_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 Compartment

J3044_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 Collisions

2016-01-149404/05/2016

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 Optimization

2016-01-153504/05/2016

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 Vehicle

2016-01-145204/05/2016

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 Countermeasures

2015-01-145904/14/2015

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 Situations

2015-01-141404/14/2015

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 Compartment

J3044_201406 (Historical)06/25/2014

Truck Crashworthiness Committee

New Trial Analysis of Characteristics of Accidents and Traffic Violations by Elderly Drivers in Japan

2014-01-912705/09/2014

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

A Study on Modeling of Driver's Braking Action to Avoid Rear-End Collision with Time Delay Neural Network

2014-01-020104/01/2014

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

The Psychological and Accident Reconstruction “Thresholds” of Drivers' Detection of Relative Velocity

2014-01-043704/01/2014

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

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

Lumbar Spine Injuries in Rear Impacts of Different Severities

2013-01-022104/08/2013

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

Impact of Driver's Steer Control on Truck-Trailer Combination when Negotiating NATO Double Lane Change Maneuver

2013-01-040404/08/2013

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

Characteristics of Accidents and Violations Caused by Elderly Drivers in Japan

2013-01-001403/25/2013

The number of elderly drivers has been increasing in Japan with the rapid progress of the nation's population aging. Securing safety for elderly drivers is an important issue in Japan. In this paper, authors conduct analysis on characteristics of accidents and violations caused by elderly drivers based on data for 2009. As there is a tendency that elderly drivers generally have less opportunity to drive vehicles than younger drivers do, it is necessary to conduct this analysis considering driving frequency when making comparison among age groups. Then, we calculated the normalized ratio (odds ratio) based on the number of rear-ended accidents in order to exclude the influence of driving frequency. As a result of the analysis, it was found that the likelihood of violations committed by elderly drivers was not particularly higher, while the likelihood of accidents caused by them was higher than younger drivers. The risk of causing an accident was judged to be about two times higher in

Morita, Kazumoto, Sekine, Michiaki

Controlling Vehicle Platoon to Alleviate Shockwave Propagation

2013-01-002203/25/2013

In this study, a scheme for controlling the deceleration rate required to alleviate shockwave propagation in a vehicle platoon is proposed. Assuming a three-vehicle platoon, the deceleration rates of the 2nd and the 3rd vehicles were modeled so as to minimize the speed of the shockwave that propagates through the platoon. The effect of the decelerating two vehicles on a 4th following vehicle was also evaluated. Numerical analysis showed that an earlier and slightly more rapid deceleration rate significantly decreased the speed of the shockwave propagated by the first three vehicles. Furthermore, even though the shockwave was amplified through the 2nd to 4th vehicles, this negative effect could be eliminated by applying the same control strategy to the 3rd and 4th vehicles.

Suzuki, Hironori, Katayama, Tsuyoshi

Representativeness and Weighting Methods of Real Time Accident Data in India

2013-26-002201/09/2013

The 2011 Report of Ministry of Road Transport and Highways, Government of India states that the total accidents with injuries is estimated about 497, 686 out of which the injuries are 511, 394 and fatalities are 142, 485, an average of one fatality per 3.5 [1]. Social losses on account of these crashes are estimated at over Rupees 100 000 Crores annually or 3% of our Gross Domestic Product (GDP) [2]. The irony is that these causalities are rising at 5.9 % annually. India accounts for 10% of the global road crash fatalities. Therefore traffic safety became very important in India. In order to understand the root causes of accidents data is needed in more detail which could be analyzed and points out the major issues to find solutions to stop this trend. Besides vehicle safety, infrastructure related issues and education skills can be derived out of accident data. Official statistics regarding accidents in India are available in national and state wise reports. More detailed information

Kumaresh, Girikumar, Lich, Thomas, Moennich, Jorg, Georgi, Andreas

Evaluation of the Internal and External Biofidelity of Current Rear Impact ATDs to Response Targets Developed from Moderate-Speed Rear Impacts of PMHS

2012-22-000510/29/2012

The goal of this study is to evaluate both the internal and external biofidelity of existing rear impact anthropomorphic test devices (BioRID II, RID3D, Hybrid III 50th) in two moderate-speed rear impact sled test conditions (8.5g, 17 km/h; 10.5g, 24 km/h) by quantitatively comparing the ATD responses to biomechanical response targets developed from PMHS testing in a corresponding study. The ATDs and PMHS were tested in an experimental seat system that is capable of simulating the dynamic seat back rotation response of production seats. The experimental seat contains a total of fourteen load cells installed such that external loads from the ATDs and PMHS can be measured to evaluate external biofidelity. The PMHS were instrumented to correspond to the instrumentation contained in the ATDs so that direct comparison between ATDs and PMHS could be made to evaluate internal biofidelity. The NHTSA Biofidelity Ranking system was used to quantitatively evaluate the biofidelity of the ATDs and

Moorhouse, Kevin, Donnelly, Bruce, Kang, Yun-Seok, Bolte IV, John H, Herriott, Rodney

Biomechanical Responses of PMHS in Moderate-Speed Rear Impacts and Development of Response Targets for Evaluating the Internal and External Biofidelity of ATDs

2012-22-000410/29/2012

The objectives of this study were to obtain biomechanical responses of post mortem human subjects (PMHS) by subjecting them to two moderate-speed rear impact sled test conditions (8.5g, 17 km/h; 10.5g, 24 km/h) while positioned in an experimental seat system, and to create biomechanical targets for internal and external biofidelity evaluation of rear impact ATDs. The experimental seat was designed to measure external loads on the head restraint (4 load cells), seat back (6 load cells), and seat pan (4 load cells) such that subject dynamic interaction with the seat could be evaluated. This seat system was capable of simulating the dynamic characteristics of modern vehicle seat backs by considering the moment-rotation properties of a typical passenger vehicle, thus providing a more realistic test environment than using a rigid seat with a non-rotating seat back as done in previous studies. Instrumentation used to measure biomechanical responses of the PMHS included both accelerometers

Kang, Yun-Seok, Bolte IV, John H, Moorhouse, Kevin, Donnelly, Bruce, Herriott, Rodney, Mallory, Ann

Standard No. 125; Warning devices.

TITLE49-SEC571-125-2012

10/01/2012

Kinematics Validation of Age-Specific Restrained 50 ^th Percentile Occupant FE Model in Frontal Impact

2012-01-056504/16/2012

Recently, the global increase of elderly vehicle users has become an issue to be considered in the effort of enhancing safety performance of vehicle restraint system. It is thought that an evaluation tool for the system representing properties of age-specific human body will play a major role for that. In previous research, the authors had developed age-specific component finite element (FE) models for the lower limb, lumbar spine, and thorax representing the adult and elderly occupants. However, the models have not been validated in terms of full body kinematics. It is essential for such models to be validated in terms of full body kinematics in order to ensure validity of the results of the assessment of the safety performance of restraint systems. In the present research, the adult and elderly occupant full body FE models were developed by incorporating the lower limb, lumbar spine and thorax of the adult and elderly FE models established in previous research. To represent the

Ito, Yuichi, Dokko, Yasuhiro, Motozawa, Yasuki, Mori, Fumie, Ohashi, Kazuki

Investigation on Occupant Ejection in High Severity Rear Impact based on Post Mortem Human Subject Sled Tests

2011-22-000511/07/2011

Occupant protection in rear impact involves two competing challenges. On one hand, allowing a deformation of the seat would act as an energy absorber in low severity impacts and would consequently decrease the risk of neck injuries. However, on the other hand, large deformations of the seat may increase the likelihood of occupant ejection in high severity cases. Green et al., 1987 analyzed a total of 919 accidents in Great Britain. They found that occupant ejection resulted in a risk of severe injuries and fatalities between 3.6 and 4.5 times higher than those cases where no ejection was observed. The sample included single front, side and rear impacts as well as multiple impacts and rollover. The rate of belt use in the sample was 50%. While this analysis included all forms of impact scenarios, nevertheless, it highlights the relative injury severity of occupant ejection. Extensive literature search has found no full-scale rear impact tests involving Post Mortem Human Subjects (PMHS

Petit, Philippe, Luet, Carole, Potier, Pascal, Vallancien, Guy

On driver distraction, the ‘eyes’ have it

11AEID0621_0106/21/2011

There is disagreement among researchers about how significant a problem mind-off-the-road is, but everyone agrees it's a good idea to look where you're going. Keeping one's attention trained entirely on operating the vehicle is asking too much of the average person, research suggests. Racecar drivers can stay focused, but the rest of us generally have something else on our minds while we're tooling down the highway. That particular state of affairs on our roadways, and in our minds, causes less worry for Ford driver distraction expert Louis Tijerina than it might for the average person. Were it not for hard data supporting his attitude, he might not have arrived at this seemingly counterintuitive view of the matter.

Ponticel, Patrick

Collision Deformation Classification

J224_201105 (Historical)05/18/2011

Data Collection and Archiving Standards Committee

Basilar Skull Fractures by Crash Type and Injury Source

2011-01-112604/12/2011

Purpose: This study investigates NASS-CDS data on basilar skull fractures by crash type and injury source for various crash scenarios to understand the injury risks, injury mechanisms and contact sources. Methods: 1993-2008 NASS-CDS data was used to study basilar skull fractures in adult front occupants by crash type and injury source. Injury risks were determined using weighted data for occupants with known injury status in 1994+ model year vehicles. In-depth analysis was made of far-side occupants in side impacts and rear crashes using the NASS electronic cases. Results: Basilar skull fractures occur in 0.507 ± 0.059% of rollovers and 0.255 ± 0.025% of side impacts. The lowest risk is in rear impacts at 0.015 ± 0.007%. The most common contact source is the roof, side rails and header (39.0%) in rollovers, the B-pillar (25.8%) in side impacts and head restraint (55.3%) in rear crashes. Seatbelt use significantly lowers the risk for basilar fracture from 1.77 ± 0.32% for unbelted to

Parenteau, Chantal, Viano, David C.

Comparing Dolly Rollover Testing to Steer-Induced Rollover Events for an Enhanced Understanding of Off-Road Rollover Dynamics

2011-01-111204/12/2011

The field of motor vehicle rollover research and testing has been one of multiple and varied approaches, dating back to at least the 1930's. The approach has been as simple as tipping a vehicle over at the top of a steep hill ( Wilson et al., 1972 ), to as complex as releasing a vehicle from an elevated roll spit mounted to the rear of a moving tractor and trailer ( Cooper et al., 2001 and Carter et al., 2002 ). Between these extremes exists numerous other rollover initiation methods, including driving a vehicle into a ramp, sliding a vehicle sideways into soil or a curb-like obstruction, launching or releasing a vehicle from a dolly cart, and remotely steering a moving vehicle into an orientation that will produce a rollover event ( Cooperrider et al., 1990 and Larson et al., 2000 ). Each method has its own unique advantages and limitations, including degrees of initial and early condition repeatability, availability for robust dynamic documentation, and degree of applicability to

Luepke, Peter, Asay, Alan

Investigation of Rear Occupant Head Restraint Interaction in High-Severity Rear Impact using BioRID and HIII

2011-01-027304/12/2011

The rear seat occupant has been the subject of an increasing number of research efforts in recent years. However, the majority of the research has focused on frontal impact, while there are also a number of studies concerned with low to moderate delta-V rear impact. Very limited work exists regarding the fate of the rear seat occupant involved in high-severity rear impact, especially when utilizing the BioRID anthropomorphic test device (ATD). Furthermore, it is evident that the out of position rear occupant, as defined by leaning forward prior to rear impact, is also of relevance to this line of research. The objective of this study is to explore and compare the response of BioRID and 50 th percentile Hybrid III in conjunction with the effects of head restraint geometry and the occupant seating configuration (normal seating versus forward leaning) in high-severity rear impact tests. Using a deceleration sled, BioRID and 50 th percentile Hybrid III were placed in the rear seat and

Braganza, Jeffrey, Tavakoli, Massoud S., Brelin-Fornari, Janet

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