Browse Topic: Accident types

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Identification of Dynamic Rollover Precursors for Enhanced Helicopter Flight Data Monitoring (HFDM) ApplicationsF-0081-2025-01465/20/2025
Dynamic rollovers represent a major hazard for helicopters during near-ground operations, often resulting in significant aircraft damage and passenger injuries. To improve safety in operations, recent studies have focused on developing a Helicopter Flight Data Monitoring framework to provide data-driven insights on operational safety. This work contributes to that effort by proposing an approach to identify precursors to dynamic rollovers. According to NTSB reports, approximately 60% of such incidents occur during in-flight phases like hover, hover-taxi, or landing. To capture the complex non-linear dynamics of helicopters, physics-based simulations were conducted to estimate a first hitting time metric, defined as the time until blade-ground contact, across a wide range of initial conditions for an inflight initial state of the helicopter. Eight parameters were identified as driving the first hitting time, and a probabilistic model was created to predict the distribution of that metric for different values of those parameters. Based on the predicted distributions, a risk-based metric was derived to robustly assess the risk of dynamic rollover and identify safer operational boundaries.
Johnson, Charles, Mavris, Dimitri
REDUCED ORDER MODELLING METHOD (ROMM) FOR GROUND VEHICLE ROLLOVER PROTECTION M&S2024-01-390311/15/2024
ABSTRACT The performance of ground vehicles during a rollover event is an important safety and occupant protection requirement for military vehicles. Modeling and simulation is a very useful tool in study and investigation of vehicle rollover characteristics and countermeasure concepts. This study presents two methods of simulating the rollover events. The first one uses Full System Method (FSM), where all the components are modelled as is and are evaluated. The second method is a reduced order modelling method (ROMM) using integration of the resulted kinematics data from FSM into the vehicle model with occupant & restraints. The FSM & ROMM methods were applied to simulate two HMMMV rollover events, and the results from both methods show that simulation and test data agreed fairly well. Computational time reduced by the ROMM was about 53% of that of the FSM. ROMM approach not only saves significant computational time but also increases robustness of the simulation. Citation: V. Babu, J. Kang, S. Kankanalapalli, J. Sheng, M. Vunnam, S. K. Karwaczynski, C. Jessup, M. Duncan, K. Paulson, “REDUCED ORDER MODELLING METHOD (ROMM) FOR GROUND VEHICLE ROLLOVER PROTECTION M&S”, In Proceedings of the Ground Vehicle Systems Engineering and Technology Symposium (GVSETS), NDIA, Novi, MI, Aug. 10-12, 2021.
Babu, V., Kang, J., Kankanalapalli, S., Sheng, J., Vunnam, M., Karwaczynski, S. K., Jessup, C., Duncan, M., Paulson, K.
Title updates jmsSAE-PP-004008/13/2021
Abstract
Jackson, Alyssa
A Comparative Life Cycle Assessment of Magnesium Front End Autoparts: A Revision to 2010-01-0275SAE-PP-001851/29/2021
The Magnesium Front End Research and Development (MFERD) project under the sponsorship of Canada, China, and USA aims to develop key technologies and a knowledge base for increased use of magnesium in automobiles. The primary goal of this life cycle assessment (LCA) study is to compare the energy and potential environmental impacts of advanced magnesium based front end parts of a North American-built 2007 GM-Cadillac CTS using the current steel structure as a baseline. An aluminium front end is also considered as an alternate light structure scenario. A “cradle-to-grave” LCA is conducted by including primary material production, semi-fabrication production, autoparts manufacturing and assembly, transportation, use phase, and end-of-life processing of autoparts. This LCA study was done in compliance with international standards ISO 14040:2006 [1] and ISO 14044:2006 [2]. While weight savings result in reductions of energy use and climate change emissions during the use phase of the car, the impacts of autoparts manufacturing and end of life recycling phases of lightweight autoparts designs are substantial as well. Pathways for improving sustainability of magnesium use in automobiles through material management and technology improvements including recycling are also discussed. Mg lightweight designs contribute to the largest use phase total primary and climate change savings over the vehicle's life time. Sustainably manufactured and recycled large magnesium structural parts can provide environmental benefits in terms of climate change emissions and consequently energy use vis-à-vis steel within the expected life of the vehicle. Overall, the aluminum lightweight design showed the best breakeven vehicle distance travelled from primary energy use and climate change perspectives within the vehicle's life time.
Mutagaana, Festo
Occupant Restraint Dynamic System Evaluation - Frontal Impact Heavy TrucksJ2418_202011 (Current)11/9/2020
This SAE Recommended Practice describes the test procedures for conducting frontal impact restraint tests for heavy truck applications. Its purpose is to establish recommended test procedures that will standardize restraint system testing for heavy trucks. Descriptions of the test set-up, test instrumentation, photographic/video coverage, and the test fixtures are included.
Truck Crashworthiness Committee
Articulated Vehicle Lateral Stability Management via Active Rear-Wheel Steering of Tractor Using Fuzzy Logic and Model Predictive Control02-13-02-00087/1/2020
In-phase rear-wheel steering, where rear wheels are steered in the same direction of front wheels, has been widely investigated in the literature for vehicle stability improvements along with stability control systems. Much faster response can be achieved by steering the rear wheels automatically during an obstacle avoidance maneuver without applying the brakes where safe stopping distance is not available. Sudden lane change movements still remain challenging for heavy articulated vehicles, such as tractor and semitrailer combinations, particularly on roads with low coefficient of adhesion. Different lateral accelerations acting on tractor and semi-trailer may cause loss of stability resulting in jackknifing, trailer-swing, rollover, or slip-off. Several attempts have been made in the literature to use active steering of semi-trailer’s rear wheels to prevent jackknifing and rollover. However, loss of stability in an articulated vehicle is usually caused by an oversteered tractor, and the semitrailer’s rear wheels have little effect on the tractor’s directional control. In this study, viability of active rear-wheel steering of tractor to maintain the stability of an articulated vehicle during a high-speed obstacle avoidance maneuver is investigated. Two different controllers, fuzzy logic and linear model-based predictive controllers, are proposed to minimize the off-tracking behavior of an articulated vehicle. The controllers were tested in IPG/TruckMaker environment with MATLAB/Simulink interface on roads with various coefficient of adhesions, performing single lane change maneuvers. The simulated results showed that jackknifing occurring right after sudden lane changes can be successfully prevented using the tractor’s active rear-wheel steering based on model predictive control algorithm when the feedback gains are tuned correctly.
Sahin, Hasan, Akalin, Ozgen
A Novel Prediction Algorithm for Heavy Vehicles System Rollover Risk Based on Failure Probability Analysis and SVM Empirical Model2020-01-07014/14/2020
The study of heavy vehicles rollover prediction, especially in algorithm-based heavy vehicles active safety control for improving road handling, is a challenging task for the heavy vehicle industry. Due to the high fatality rate caused by vehicle rollover, how to precisely and effectively predict the rollover of heavy vehicles became a hot topic in both academia and industry. Because of the strong non-linear characteristics of Human-Vehicle-Road interaction and the uncertainty of modeling, the traditional deterministic method cannot predict the rollover hazard of heavy vehicles accurately. To deal with the above issues, this paper applies a probability method of uncertainty to the design of a dynamic rollover prediction algorithm for heavy vehicles and proposes a novel algorithm for predicting the rollover hazard based on the combined empirical model of reliability index and failure probability. Moreover, the paper establishes a classification model of heavy vehicles based on the support vector machine (SVM) and uses the Monte Carlo method to calculate the failure probability of rollover limit state of heavy vehicles. The fishhook, double lane change, and slalom maneuver tests of heavy vehicles are used to predict and validate the proposed algorithm in real-time. The simulation results show that the rollover prediction method based on failure probability is accurate and real-time, and can effectively improve the rollover prediction accuracy. Meanwhile, the proposed approach reduces the external interference of strong non-linear characteristics of Human-Vehicle-Road interaction and the uncertainty of the modeling to the system, thus significantly improving the prediction accuracy of active safety performance of heavy vehicles.
Zhu, Tianjun, Yin, Xiaoxuan, Wang, Zhenfeng, Wang, Dong, Li, Fei, Wang, Xinyu, Ma, Wei, Wang, Zheng
Evaluation of General Motors Event Data Recorder Performance in Semi-Trailer Rear Underride Collisions2020-01-13284/14/2020
The objective of this study was to analyze the validity of airbag control module data in semi-trailer rear underride collisions. These impacts involve unusual collision dynamics, including long crash pulses and minimal bumper engagement [1]. For this study, publicly available data from 16 semi-trailer underride guard crash tests performed by the Insurance Institute for Highway Safety (IIHS) were used to form conclusions about the accuracy of General Motors airbag control module (ACM) delta-V (ΔV) data in a semi-trailer rear underride scenario. These tests all utilized a 2009 or 2010 Chevrolet Malibu impacting a stationary 48’ or 53’ semi-trailer at a speed of 35 mph. Nine tests were fully overlapped collisions, six were 30% overlapped, and one was 50% overlapped [2]. The IIHS test vehicles were equipped with calibrated 10000 Hz accelerometer units. Event Data Recorder (EDR) data imaged post-accident from the test vehicles were compared to the reference IIHS data. For each test, root mean square error (RMSE), the percent error over time, and the difference between the EDR ΔV and the IIHS ΔV, was quantified, plotted, and related to crash pulse. This analysis revealed a general trend of decreasing EDR ΔV parity with an increasing crash pulse duration, although overall differences remained low for most tests. Eleven tests, all with airbag deployments, converged towards an average of 3.3% error at the end of the crash pulse, which were 150-270 ms. EDR recorded ΔVs were in the range of 29.8-39.9 mph. Five tests, three of which were non-deployments, diverged to higher percentage error averaging 12.7% at an EDR ΔV of 31.8-40.0 mph. All higher error tests were 30% overlapped and had the highest crash pulse durations of 240-300 ms. One fully overlapped test generated highly unusual EDR data due to failure of the rear underride guard mounting bolts and plates.
Famiglietti, Nicholas, Hoang, Ryan, Fatzinger, Edward, Landerville, Jon
Innovative Active Head Restraint System in a Car: Safety Assessment with Virtual Human Body Model2020-01-09794/14/2020
The aim of this study is to use numerical simulations for safety assessment of an innovative active head restraint system. This system was developed to protect the head and neck of an occupant in a car without a head airbag during a side impact. Its FE model is created and embedded it in a model of a small car with a side airbag. The dynamics of the head restraint activation are also taken into account. The virtual human body model Virthuman is used to represent occupants. The model is scaled for pre-selected human individuals to cover large numbers of occupants of different sizes. It extends conventional virtual evaluation of new safety designs via existing pre-defined mono-purpose side dummies and their FE models. The benefit of the head restraint system is evaluated in side impact scenarios inspired by the pole tests performed by EuroNCAP. Transversal impacts to a pole at 29 and 32 km/h are considered at 90° and 75° angles from driver and the opposite side. Also, the far side impact prescribed with an acceleration pulse according to EuroNCAP is considered. Various initial driver sizes in standard seated positions are tested. To extend the study beyond standard testing protocols, out-of-position of driver is also considered, leading to more than 100 simulations of impact scenarios in total. The effect of the innovative head restraint system is assessed from the point of view of driver injury risk.
Vychytil, Jan, Hlucha, Jana, Kovar, Ludek, Kostikova, Martina, Moravcova, Pavlina, Bucsuhazy, Katerina
Fuel Tank Dynamic Strain Measurement Using Computer Vision Analysis2020-01-09244/14/2020
Stress and strain measurement of high density polyethylene (HDPE) fuel tanks under dynamic loading is challenging. Motion tracking combined with computer vision was employed to evaluate the strain in an HDPE fuel tank being dynamically loaded with a crash pulse. Traditional testing methods such as strain gages are limited to the small strain elastic region and HDPE testing may exceed the range of the strain gage. In addition, strain gages are limited to a localized area and are not able to measure the deformation and strain across a discontinuity such as a pinch seam. Other methods such as shape tape may not have the response time needed for a dynamic event. Motion tracking data analysis was performed by tracking the motion of specified points on a fuel tank during a dynamic test. An HDPE fuel tank was mounted to a vehicle section and a sled test was performed using a Seattle sled to simulate a high deltaV crash. Multiple target markers were placed on the fuel tank. The motion of these markers was captured using high speed video cameras. The high speed videos were processed using the OpenCV computer vision library. Using OpenCV, the high speed videos were imported, and the position of the central location of each target marker was extracted frame by frame from the high speed videos. Once the position was known, the strain was computed using the change in relative position between two marker positions. Results of the testing showed that the acceleration-induced strain is low, generally less than the material yield strain. It was noted that reliable and accurate results require that the camera be placed normal to, or at a shallow angle to, the points being tracked. In addition, curved surfaces lead to limited fidelity of strain data due to the varying focal length of the points being tracked and measurement increased sensitivity. This method is similar to a “typical” tensile test in which displacement is tracked between two pre-established points on a sample. As such, the methodology was replicated on a tensile specimen to validate the methodology.
Fleming, Mark, Krishnaswami, Ram, Nakamoto, Kunihiro
Perceptions of Two Unique Lane Centering Systems: An FOT Interview Analysis2020-01-01084/14/2020
The goal of this interview analysis was to explore and document the perceptions of two unique lane centering systems (S90’s Pilot Assist and CT6’s Super Cruise). Both systems offer a similar type of functionality (adaptive cruise control and lane centering), but have significantly different design philosophies and HMI (Human-Machine Interface) implementations. Twenty-four drivers drove one of the two vehicle models for a month as part of a field operational test (FOT) study. Upon vehicle return, drivers took part in a 60-minute semi-structured interview covering their perceptions of the vehicle’s various advanced driver-assistance systems (ADAS). Transcripts of the interviews were coded by two researchers, who tagged each statement with relevant system and perception code labels. For analysis, the perception codes were grouped into larger thematic bins of safety, comfort, driver attention, and system performance. Perceptions of adaptive cruise control (ACC) were similar across vehicles. Almost all participants mentioned benefits of comfort and safety associated with ACC use. Participants cited different benefits between the two vehicle’s implementations of lane centering. A majority of participants (75%) described comfort benefits associated with Super Cruise, while less than half (41%) cited comfort benefits associated with Pilot Assist. Only a few participants (25%) mentioned safety benefits associated with Super Cruise. Half (50%) of the participants mentioned safety benefits associated with Pilot Assist. Almost all participants cited fears of potential misuse of the system in which drivers might pay less attention to the driving task. Results suggest that drivers’ comprehension and expectation of these systems’ behavior are strongly influenced by their design philosophies, specifically in terms of the difference in hands-on versus hands-off-wheel implementation. The perceived role of the driver – as either a fallback driver or as an assisted driver - may be influenced by the design implementation.
Landry, Steven, Seppelt, Bobbie, Russo, Luca, Mehler, Bruce, Angell, Linda, Gershon, Pnina, Reimer, Bryan
Development of a Procedure to Correlate, Validate and Confirm Radar Characteristics of Surrogate Targets for ADAS Testing2020-01-07164/14/2020
Surrogate targets are used throughout the automotive industry to safely and repeatably test Advanced Driver Assistance Systems (ADAS) and will likely find similar applications in tests of Automated Driving Systems. For those test results to be applicable to real-world scenarios, the surrogate targets must be representative of the real-world objects that they emulate. Early target development efforts were generally divided into those that relied on sophisticated radar measurement facilities and those that relied on ad-hoc measurements using automotive grade equipment. This situation made communication and interpretation of results between research groups, target developers and target users difficult. SAE J3122, “Test Target Correlation - Radar Characteristics”, was developed by the SAE Active Safety Systems Standards Committee to address this and other challenges associated with target development and use. J3122 addresses four topics. First, it describes standardized equipment and procedures for making various types of calibrated radar measurements using automotive grade equipment, with minimal measurement site restrictions. Second, a correlation procedure is provided that is used to define validity regions and properties of representative real-world objects. Third, a validation procedure is provided for comparing candidate targets against measurements of representative objects using an objective correlation score. Finally, a confirmation procedure is provided for checking in-use targets to verify that they continue to be acceptable for testing. This paper describes each of these topics as well as the process development.
Silberling, Jordan, Nicols, George, Buller, William, Lenkeit, John
The Effects of Small Seat Swiveling Angles on Occupant Responses during a Frontal Impact2020-01-05714/14/2020
In highly automated vehicles (HAVs), new seat configurations may be desirable to allow occupants to perform new activities. One of the current HAV concepts is the swiveled seat layout, which might facilitate communication between occupants. The main objective of this study was to investigate the effects of seat swiveling angles on occupant kinematics and injury risk predicted by a Human Body Model (HBM) during a frontal impact. A detailed 50th percentile male HBM (GHBMC M50-O) was subjected to two frontal crash pulses in a sled setup. The model was positioned on a semi-rigid seat and restrained using a pre-inflated airbag and a three-point seatbelt. Simulations included four seat swiveling angles (0, -10, -20, and -30 degrees), three occupant positions (Sedan driver, large VAN driver or Laptop user), two airbag initial locations (nominal or matching the head Y location), and the inclusion of lateral supports on the seat pan. The effects of the seat swiveling angle were similar for all occupant positions. With the airbag in the nominal location, higher seat swiveling angles led to a higher head lateral displacement and a higher risk of head injury, especially for the BrIC criterion. The Sedan driver position had higher BrIC and a larger head lateral excursion than the other two positions. This could be mitigated by aligning the airbag location with the head. Pelvic fractures were also predicted for the configurations with the highest swiveling angles. These fractures were limited by the use of seat pan lateral supports. Overall, the model responses were sensitive to both seating configurations and occupant postures, and the results suggest that swiveled seating may increase the injury risk, especially for the head and pelvis. However, simple countermeasures, such as adapted airbag location or adding lateral seat pan supports, seemed possible to mitigate the risk.
Grébonval, Cyrille, Trosseille, Xavier, Petit, Philippe, Wang, Xuguang, Beillas, Philippe
SUV Kinematics during a Steer-Induced Rollover Resolved Using Consumer-Grade Video, Laser Scans and Match-Moving Techniques2020-01-06424/14/2020
Rollover crashes are complex events that generate motions in all six degrees of freedom (6DOF). Directly quantifying the angular rotations from video can be difficult and vehicle orientation as a function of time is often not reported for staged rollover crashes. Our goal was to evaluate the ability of using a match-moving technique and consumer-grade video cameras to quantify the roll, pitch and yaw angles and angular velocities of a rollover crash. We staged a steer-induced rollover of an SUV at 106 km/h. The vehicle was fitted with tri-axial accelerometers and angular rate sensors, and five consumer-grade video cameras (2 on tripods, 2 on drones, 1 handheld, ~30 fps) captured the event. Roll, pitch and yaw angles were determined from the video using specialized software. We then compared the vehicle orientation angles from the video data to the integrated angular rate data measured by onboard sensors, and also compared the angular rates from the differentiated video data to the angular rates measured directly by the sensors. We found that both methods of measuring the 3D angles and angular rates generated similar results. The integrated sensor data drifted a maximum of 13° relative to the video-based angles, with RMS differences of ±2.7° or less when the drift was removed. The differentiated video data did not drift relative to the sensor data, with RMS differences of ±0.22 rad/s or less. These findings indicate that both methods generate similar results and are suitable for reconstructing rollovers. Given the drift we observed in the integrated sensor data, we recommend using angle measurements from the video to quantify the amount of drift in integrated sensor data if accurate knowledge of the vehicle’s orientation as a function of time is important.
Young, Cole R., King, David J., Siegmund, Gunter P.
Likelihood of Spinal Disc Herniations in Occupants Involved in Real World Side Impacts2020-01-05264/14/2020
The prevalence of spinal disc herniations in people with no spinal symptoms have been reported to increase with age; from about 20% in those below 40 years to about 30% in those above 40 years. Spinal disc herniations are usually associated with degenerative changes. Though rare, spinal disc herniations can also be caused by trauma. With an increasing number of older people on U.S. roads with a concomitant increase in the probability of getting injured in a vehicle collision, it is reasonable to expect that some of these occupants can present with clinical findings of spinal disc herniations after a side impact, and attribute these findings to the impact. In this study, we looked at the relationship between real world side impacts and the occurrence of spinal injuries, in particular disc herniations, in occupants involved in such impacts. We examined the reported occurrence of all spine injuries in side impact crashes in the National Automotive Sampling System - Crashworthiness Data System (NASS-CDS) database from 1993 through 2014. There were over 8,400 adult raw case occupants, corresponding to a weighted number of approximately 4.7 million that fit the inclusion criteria. The results showed that the most common spine injury in side impact is acute muscle strain of the cervical spine, followed by acute muscle strain of the lumbar spine. The total number of occupants with reported spinal disc herniations was only three; all from near-side impacts. The low prevalence of reported spinal disc herniations stands in sharp contrast to a background prevalence of 20% to 30% in asymptomatic individuals. The findings from the real world data in this study, in light of known spinal responses in experiments conducted on post-mortem human subjects (PMHSs) and anthropomorphic test devices (ATDs) exposed to near- and far-side impacts, suggest that side impacts do not present a mechanism of traumatic disc herniation.
Lam, Tack, Ivarsson, B. Johan
Automated Driving System Data LoggerJ3197_202004 (Historical)4/11/2020
This recommended practice provides common data output formats and definitions for a variety of data elements that may be useful for analyzing the performance of automated driving system (ADS) during an event that meets the trigger threshold criteria specified in this document. The document is intended to govern data element definitions, to provide a minimum data element set, and to specify a common ADS data logger record format as applicable for motor vehicle applications. The data elements defined in this document are unique to Levels 3, 4, or 5 ADS features, as defined by SAE J3016, and provide additional background of the events leading up to a crash or crash-like event. The data from sensors such as camera(s), LiDAR(s) etc. will provide information in the absence of a human driver. The data included in the ADS data logger is expected to be used in conjunction with the SAE J1698 EDR record and traditional accident reconstruction analysis. The event data recorder (EDR) and ADS data logger will capture information leading up to the triggered event, at a minimum. ADS technology is still being developed and is not yet commercially deployed. Therefore, this SAE Recommended Practice is intended as a guide toward standard practice and is subject to change to keep pace with experience and technical advances.
Event Data Recorder Committee
Investigating Combined Thoracic Loading Using the Elderly Female Dummy (EFD)2019-22-00173/31/2020
The Elderly Female Dummy (EFD) is an omni-directional ATD developed to represent a vulnerable population. The EFD it is able to be 3D printed and quickly altered to meet design requirements. A recent side impact sled test series suggested that small, elderly females may be at risk of thoracic injuries in side impact crashes due to combined loading from the belt pre-tensioner and side airbag. The EFD was altered to add four IR-TRACCs to the thoracic region to allow both x-axis and y-axis displacement to be evaluated in a similar test. While the IR-TRACCs did record the displacement due to combined loading, the rate of displacement and timing of the peak displacements did not match external chestband outputs. The next step for the EFD is to revise the locations of IRTRACCs in the thorax and begin component testing in lateral and frontal directions to improve thoracic biofidelity.
Beebe, Michael, Sullenberger, Kris, Burleigh, Mark, McCarthy, Joe, Bolte IV, John H
Optimization of Braking Strategy for Automatic Emergency Braking System in Vehicle-Pedestrian Accidents07-12-02-00093/23/2020
Braking strategy is the core of the automatic emergency braking (AEB) system. How to make the braking strategy of the AEB system more suitable for real traffic conditions and more acceptable to drivers is a very important research. This article carries out the braking strategy optimization for the AEB system. From the vehicle-pedestrian accidents collected by the National Automobile Accident In-depth Investigation System (NAIS) of Songjiang Station, this article selects typical cases equipped with event data recorder (EDR) and then analyzes the EDR data. On this basis, the strategy for the optimization of the AEB system is formed. The optimized strategy is simulated in the test scenario specified in the European New Car Assessment Programme (Euro-NCAP) and compared with the real vehicle test results. The result illustrates that the optimized braking strategy is more effective to avoid or mitigate collisions.
Qian, Yubin, Yang, Xueyan, Xiao, Lingyun, Zhu, Yican
Influence Analysis of AEB Two-Wheeler on Passenger Car Impact Two-Wheeler Traffic Accidents in China2020-01-50232/24/2020
AEB two-wheeler system is an active safety technology which developed for avoiding two-wheeler accidents. With a large number of two wheelers, China needs to conduct research and analysis of this system. In this paper, real traffic accident data in China are used to analyze the possible influence of AEB two-wheeler system on traffic accidents. The paper chooses real passenger car impact two wheeler accidents happen in China, and gets the characteristics of data analysis. Then the paper analysis the influence of AEB system using position data when TTC=3s. According to the analysis, the detection range of 90 meters and the detection angle of 45 degrees can improve the recognition rate of day crossing accident by 17.7%, night crossing accident by 21.5% and longitudinal accident by 38.8%. The paper provides effective support for the development and test of AEB two-wheeler system in China. Car-to-two-wheeler accident AEB two-wheeler system Influence of the accident
Xudong, Li, Xiaowei, Lian, Xingchang, Wang
Message Sets for Advanced Traveler Information System (ATIS)J2354_201906 (Current)6/11/2019
This SAE Standard describes standardized medium-independent messages needed by information service providers for Advanced Traveler Information Systems (ATIS). The messages contained herein address all stages of travel (informational, pre-trip and en route), all types of travelers (drivers, passengers, personal devices, computers, other servers), all categories of information, and all platforms for delivery of information (in-vehicle, portable devices, kiosks, etc.).
V2X Core Technical Committee
Accuracy and Sensitivity of Yaw Speed Analysis to Available Data2019-01-04174/2/2019
Accident reconstructionists rarely have complete data with which to determine vehicle speed, and so the true value must be bracketed within a range. Previous work has shown the effect of friction uncertainty in determining speed from tire marks left by a vehicle in yaw. The goal of the current study was to assess improvements in the accuracy of vehicle speed estimated from yaw marks using progressively more scene and vehicle information. Data for this analysis came from staged S-turn maneuvers that in some cases led to rollover of sport utility vehicles. Initial speeds were first calculated using the critical curve speed (CCS) formula on the yaw marks from the first portion of the S-maneuver. Then computer simulations were performed with progressively more input data: i) the complete tire marks from the whole S-maneuver, ii) measured vehicle mass, iii) measured suspension stiffness and damping, and iv) measured steering history. Simulations based on the complete tire marks reduced the average error compared with the CCS equation if measured accelerations were also matched. Adding the remaining input data to the simulations did not further improve the accuracy of the reconstructed vehicle speed.
Heinrichs, Bradley, Lee, Janice, Young, Cole
Naturalistic Driving Behavior Analysis under Typical Normal Cut-In Scenarios2019-01-01244/2/2019
Cut-in scenarios are common and of potential risk in China but Advanced Driver Assistant System (ADAS) doesn’t work well under such scenarios. In order to improve the acceptance of ADAS, its reactions to Cut-in scenarios should meet driver’s driving habits and expectancy. Brake is considered as an express of risk and brake tendency in normal Cut-in situations needs more investigation. Under critical Cut-in scenarios, driver tends to brake hard to eliminate collision risk when cutting in vehicle right crossing lane. However, under less critical Cut-in scenarios, namely normal Cut-in scenarios, driver brakes in some cases and takes no brake maneuver in others. The time when driver initiated to brake was defined as key time. If driver had no brake maneuver, the time when cutting-in vehicle right crossed lane was defined as key time. This paper focuses on driver’s brake tendency at key time under normal Cut-in situations. Environment factors (for example, traffic condition and road type), cutting-in vehicle type and motion factors were considered as influence factors. To comprehensively take those factors into account, cluster analysis was adopted to extract typical Cut-in scenarios from naturalistic driving database. Seven typical scenarios as well as driver’s behavior data were obtained. It is found that there exists certain linear relationship between Time headway (THW, equals to relative distance divided by subject vehicle velocity) and relative velocity. The linear correlation of brake cases is good, but linearity of no brake cases is weak. In each typical Cut-in scenario, driver's brake behavior was demonstrated by scatter plot on THW-relative velocity plane. This plane was divided into several zones where driver tends to brake or not to brake. A special situation is that cutting-in vehicle surpasses subject vehicle and merges in a brutal way and under such situation driver will brake hard.
Ma, Xuehan, Ma, Zhixiong, Zhu, Xichan, Cao, Jianyong, Yu, Feng
Study on a Method for Evaluating the Safety of the Braking Control Algorithm for Automated Driving System When Following2019-01-10154/2/2019
The purpose of this study is to develop a method for evaluating the safety of the braking control algorithm for automated driving under mixed traffic flow of automated driving system and vehicles driven by drivers. We consider that the automated driving system should be controlled such that it blends in with mixed traffic. Therefore, in evaluating the safety of braking control for the automated driving system when following, the influence of the automated driving system on the driver of the following vehicle is an important evaluation index. First, we analyzed past traffic accidents in Japan to determine a suitable traffic environment for evaluating the safety of the braking control algorithm for the automated driving system when following. Second, the driver’s braking operations were measured using actual vehicles in this situation. We developed a method of generating sample algorithms of braking control based on the driver’s braking operations. Finally, we developed a method of identifying the most suitable range of parameters of braking control algorithms by evaluating these sample algorithms based on the results of actual experiments. This evaluation method uses a driving simulator. The automated driving system in which the sample algorithm of braking control is installed runs ahead of the vehicle driven by a subject in the driving simulator. The subject evaluates the sense of danger for braking by the automated driving system.
Gokan, Masato, Tanaka, Nobuhisa, Furukawa, Yoshimi, Iwase, Tunetoshi, Hirowatari, Taichi
Head and Neck Loading Conditions over a Decade of IIHS Rear Impact Seat Testing2019-01-12274/2/2019
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 simulation sled and accelerated to represent a rear crash with a delta-V of approximately 15.6 kph (15.6 ± 0.26 kph). Head and neck injury metrics were calculated for all tests to evaluate trends in the test ATD responses across model years. Reductions in HIC 15, Nij, and upper neck tensile forces were observed across all model years. Nkm, upper neck flexion moments, extension moments, and shear forces were found to show little or no change by model year. Reductions in time to initial contact with the head restraint were observed and likely contributed to reduced head accelerations and neck tensile forces. Given the anticipated persistence of rear-end impacts and potential changes to the vehicle interior layout with improving AV technology, the data should be considered by designers, researchers, and evaluators looking to project future crash and injury rates in rear-end impacts.
Scanlon, John M., Isaacs, Jessica, Garman, Christina
Risk of Concussion in Low- to Moderate-Speed Frontal and Rear-End Motor Vehicle Collisions Evaluated Using Head Acceleration-Based Metrics2019-01-12184/2/2019
Over the past decade, there has been an increase in awareness and concern about the occurrence and long-term effects of concussions. Traumatic brain injury (TBI)-related emergency department (ED) visits associated with motor vehicle collisions, including patients with a diagnosis of concussion or mild TBI (mTBI), have increased while deaths and hospital admissions related to TBI have decreased. The diagnostic criteria for concussion have evolved and broadened, and based on current assessments and diagnostic imaging techniques, there are often no objective findings, yet a diagnosis of concussion may still be rendered. Clinical assessment of concussion may be based only on patient-reported symptoms and history, making it difficult to objectively relate the reported increase in TBI-related ED visits due to motor vehicle collisions to specific collision parameters. This study aims to perform a scientific evaluation of concussion risk during motor vehicle collisions, strengthened by objective, quantitative data, specifically focusing on head acceleration-based metrics. Data from full-scale passenger vehicle crash tests are reported for frontal and rear-end collisions with delta-Vs ranging from 6.0 to 19.0 kph (3.7 to 11.8 mph) and 5.6 to 19.5 kph (3.5 to 12.1 mph), respectively. Head linear and rotational kinematic data were recorded from instrumented Hybrid III 50th percentile male anthropomorphic test devices (ATDs) restrained in the driver’s seats. Several acceleration-based metrics currently used to assess risk of concussion were calculated and compared to published injury risk relationships that have been developed from field accident data, human subjects, and biomechanical models. Overall, the magnitudes of acceleration were low and the injury metrics corresponded to a negligible risk of concussion in these low- to moderate-speed collisions.
Pasquesi, Stephanie A., Bruno, Alexander, Courtney, Amy, Imler, Stacy M., Smedley, Janine, Prange, Michael T.
Innovative Knee Airbag (KAB) Concept for Small Overlap and Oblique Frontal Impacts2019-01-06214/2/2019
Considerable research has been conducted in terms of attempting to reduce lower leg injury risk in full frontal impacts, in some cases by the use of a knee airbag (KAB). However, there has been limited research into the performance of KAB systems during a crash test with increased oblique loading, such as the IIHS small overlap frontal test, an oblique moving deformable barrier test (OI) being researched by NHTSA, and a mobile progressive deformable barrier test (MPDB) that is expected to be implemented by Euro NCAP in the next few years. The objective of the current numerical study was concentrated on the evaluation of an innovative KAB concept design intended to reduce ATD right inboard lower leg/foot responses under small overlap and oblique loading conditions. A novel appendage KAB concept design was developed with the help of morphing and computational studies which were performed with different ATD sizes. In the study, one of the lower leg/foot responses was monitored and compared over a conventional KAB design. Cases investigated in the study showed that the novel appendage KAB concept design acts as a conventional KAB in full frontal impact modes (similar right inboard femur responses) and has the potential to reduce right inboard lower leg/foot responses by an average 16% (small overlap impact mode) and 20% (oblique impact mode) over the conventional KAB design. Furthermore, it was noted that the novel design could potentially be adapted to achieve targeted right inboard lower leg responses in full, offset and oblique frontal crash tests with minimal impact on the left outboard responses.
Makwana, Rahul, Jindal, Pardeep
Performance of Event Data Recorders Found in Toyota Airbag Control Modules in High Severity Frontal Oblique Offset Crash Tests2019-01-06334/2/2019
This paper presents an in-depth analysis of the performance of Event Data Recorders (EDRs) found in the Airbag Control Modules (ACMs), as tested in support of the National Highway Traffic Safety Administration’s Frontal Oblique Offset Program. Previous studies have examined EDR performance in high severity full-frontal barrier crash tests and moving deformable barrier side impact tests. This paper presents data from a high severity oblique frontal impact test in which the vehicle was struck by a moving deformable barrier. This paper examines the results of EDR data downloaded from two 2015 model year Toyota Highlanders, and the results of EDR reported change in velocity (delta-v), to vehicle mounted accelerometers and reference instrumentation. This paper will analyze EDR performance in reporting: Seatbelt buckle status, Occupant Size Classification, Front Passenger, Airbag and seatbelt pretensioner deployment time(s), Longitudinal delta-v, and Lateral acceleration/crash pulse.
Bortles, William, Hostetler, Ryan
Passenger Vehicle Dynamic Response and Characterization of Side Structure during Low- to Moderate-Speed Side Impacts2019-01-04204/2/2019
A significant portion of real-world passenger vehicle side impacts occur at lower speeds than testing conducted by the National Highway Traffic Safety Administration (NHTSA) or the Insurance Institute for Highway Safety (IIHS). Test data from low- to moderate-speed side impacts involving late-model passenger vehicles is limited, making the evaluation of vehicle impact response, occupant loading, and injury potential challenging. This study provides the results of low- to moderate-speed impact testing involving a late-model mid-size sedan. Two full-scale Non-Deformable Moving Barrier (NDMB) side impact crash tests were conducted at speeds of 6.2 mph (10.0 kph) and 13.4 mph (21.6 kph). Instrumentation on the late-model sedan used for the test series included tri-axis accelerometers and seat belt load cells. In both tests, instrumented Hybrid III 50th percentile-male Anthropomorphic Test Devices (ATDs) were restrained in the driver and passenger seats using the standard three-point seat belts. Response data for the vehicle, barrier, and ATDs was recorded using onboard data acquisition, and on- and off-board real-time and high-speed video cameras. In addition, the deformation to the side of the sedan was quantified from pre- and post-test laser scan data. Results from the test series provided data regarding accelerations, velocity change, and restitution. The damage to the side structure of the vehicle was assessed and conclusions regarding damage initiation and damage progression are discussed. Conservation of Momentum and Conservation of Energy analyses are presented and force-displacement characteristics and energy dissipation were evaluated and compared. Utilizing the data that was developed from the test series, vehicle side stiffness modeling was also conducted.
Skiera, Jason, Crosby, Charles, Bare, Cleve, Paradiso, Marc, Campbell, Gregory
Estimation of the Relative Roles of Belt-Wearing Rate, Crash Speed Change, and Several Occupant Variables in Frontal Impacts for Two Levels of Injury2019-01-12194/2/2019
Driver injury probabilities in real-world frontal crashes were statistically modeled to estimate the relative roles of five variables of topical interest. One variable pertained to behavior (belt-wearing rate), one pertained to crash circumstances (speed change), and three pertained to occupant demographics (sex, age, and body mass index). The attendant analysis was composed of two parts: (1) baseline statistical modeling to help recover the past, and (2) sensitivity analyses to help consider the future. In Part 1, risk functions were generated from statistical analysis of real-world data pertaining to 1998-2014 model-year light passenger cars/trucks in 11-1 o’clock, full-engagement frontal crashes documented in the National Automotive Sampling System (NASS, 1997-2014). The selected data yielded a weighted estimate of 1,269,178 crash-involved drivers. Those data were parsed for four subpopulations: two levels of belt use (properly-belted vs. unbelted) and two levels of driver injury (moderate-to-maximum, MAIS2+ vs. serious-to-maximum, MAIS3+). For each subpopulation, a baseline statistical model was generated via logistic regression, cast as a function of the studied variables. Each risk function was assessed for statistical significance (p-value for each term) and statistical associativity (Goodman-Kruskal Gamma). The four resulting risk functions had some statistical insignificance and fair fidelity, with Gammas ranging from 0.54 to 0.73. However, the risk functions demonstrated excellent fidelity for estimating aggregate injury rates (function-estimated vs. directly-estimated). They were accordingly applied in Part 2. In Part 2, sensitivity studies were conducted by (a) perturbing the studied variables in the NASS dataset to generate thousands of hypothetical NASS files, (b) applying the risk functions to estimate attendant net injury rates, and (c) relating the net injury rates to the variations. Specifically, net injury rates and mean statistics were generated for 15,552 hypothetical NASS datasets involving both belted and unbelted drivers. Those data were then normalized by the means of the baseline NASS file. Finally, power functions were developed to relate the resulting dimensionless net injury-rate data to the five dimensionless predictor variables. Those functions demonstrated excellent fidelity (R2≥0.95), and their exponents helped quantify the relative role of the five studied variables. Belt-wearing rate and speed change were determined to be the most influential, followed by age, body mass index, and sex. These findings might help guide engineers and regulators.
Laituri, Tony, Henry, Scott, Li, Guosong
Lateral and Tangential Accelerations of Left Turning Vehicles from Naturalistic Observations2019-01-04214/2/2019
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 with a convolutional neural network designed to detect vehicles. The detected vehicles were then tracked over time and the results were analyzed. A total of 86 left turning vehicles were analyzed. In 23 of the observed turns, an oncoming vehicle was also visible in the video. The spatial relationship between the oncoming vehicles and the left turning vehicles was analyzed and the relationship between gap acceptance and acceleration is presented. Accident reconstructionists and traffic engineers can use this data to prescribe realistic values or ranges to accelerations of left-turning vehicles.
Carter, Neal, Beier, Steven, Cordero, Rheana
Cooperative Collision Avoidance in a Connected Vehicle Environment2019-01-04884/2/2019
Connected vehicle (CV) technology is among the most heavily researched areas in both the academia and industry. The vehicle to vehicle (V2V), vehicle to infrastructure (V2I) and vehicle to pedestrian (V2P) communication capabilities enable critical situational awareness. In some cases, these vehicle communication safety capabilities can overcome the shortcomings of other sensor safety capabilities because of external conditions such as 'No Line of Sight' (NLOS) or very harsh weather conditions. Connected vehicles will help cities and states reduce traffic congestion, improve fuel efficiency and improve the safety of the vehicles and pedestrians. On the road, cars will be able to communicate with one another, automatically transmitting data such as speed, position, and direction, and send alerts to each other if a crash seems imminent. The main focus of this paper is the implementation of Cooperative Collision Avoidance (CCA) for connected vehicles. It leverages the Vehicle to Everything (V2X) communication technology to create a real-time implementable collision avoidance algorithm along with decision-making for a vehicle that communicates with other vehicles. Four distinct collision risk environments are simulated on a cost effective Connected Autonomous Vehicle (CAV) Hardware in the Loop (HIL) simulator to test the overall algorithm in real-time with real electronic control and communication hardware.
Gelbal, Sukru Yaren, Zhu, Sheng, Anantharaman, Gokul Arvind, Aksun Guvenc, Bilin, Guvenc, Levent
Evaluation of Occupant Kinematics in Low- to Moderate-Speed Frontal and Rear-End Motor Vehicle Collisions2019-01-12264/2/2019
Low- to moderate-speed motor vehicle collisions are a common crash type and are sometimes associated with injury complaints. Understanding occupant motion (kinematics) in response to low- and moderate-speed motor vehicle collisions is important for evaluating occupant interactions with interior vehicle structures, including the restraint systems, with the ultimate goal of assessing injury potential. Furthermore, quantitative occupant kinematic data from full-scale crash testing of late-model passenger vehicles is limited for collisions at low- to moderate-speeds. The current study reports kinematic data from full-scale frontal and rear-end crash tests of late-model, mid-size sedans with delta-Vs ranging from 6.0 to 19.0 kph (3.7 to 11.8 mph) and 5.6 to 19.5 kph (3.5 to 12.1 mph), respectively. For each test vehicle, the motion of a Hybrid III 50th-percentile male anthropomorphic test device (ATD) restrained in the driver seat was recorded using high-speed onboard video. Motion tracking of the video was used to evaluate the excursion and velocity of each ATD’s head, shoulder, elbow, and knee with respect to the vehicle interior. Restraint loads were recorded via load cells placed on the driver’s torso and lap belts. For both the frontal and rear-end collisions, the maximum excursion and velocity of the ATD with respect to the occupant compartment generally increased with increasing delta-V. During the occupant rebound phase of the rear-end collisions, the maximum excursion and velocity of the ATD also generally increased with increasing delta-V and was generally less than its initial rearward excursion and velocity.
Bruno, Alexander, Toney-Bolger, Megan, George, Juff, Koller, Jeffrey, Filatov, Anton, Olberding, Joseph
The Kinematic Analysis of Occupant Excursions and Accelerations during Staged Low Speed Far-Side Lateral Vehicle-to-Vehicle Impacts2019-01-10304/2/2019
The collection of research regarding occupant kinematics during low speed lateral vehicle-to-vehicle impacts is far less comprehensive than the much larger body of literature that quantifies the occupant kinematics associated with low speed rear end (longitudinal) impacts. In order to augment the available data, a series of 39 low speed far-side lateral vehicle-to-vehicle impacts were conducted in a laboratory setting. A combination of accelerometers and 3D motion tracking was used to characterize the motions of both the Target and Bullet vehicles during their collisions. The Target vehicle was initially stationary; the Bullet vehicle impacted the Target vehicle at the front passenger side door. The Bullet vehicle pre-impact speeds across all tests ranged from approximately 2.5 to 5.5 mph (4.0 to 8.9 kph; 1.1 to 2.5 m/s). Eight volunteers participated in the study. Volunteers were seated in the driver seat during the impacts and were outfitted with accelerometers on their head and wore reflective markers for 3D motion tracking on the left side of their body. The experimental design included conducting lateral impacts while the volunteers were in both “non-distracted” and “distracted” states to identify any potential influence on occupant kinematics. In addition, effects of gender and anthropometry were explored. Primary outcome measures that were analyzed for each lateral impact included occupant accelerations measured at the head and the lateral displacement of the head relative to its initial position prior to impact. Volunteer peak resultant head accelerations (including gravity) ranged from 1.90 to 4.32 g. The peak Y-axis displacement of the head relative to the Target vehicle and away from the driver side B-pillar was 3.86 to 12.16 inches (9.80 to 30.89 cm) while the peak Y-axis displacement of the head relative to the Target vehicle and toward the driver side B-pillar ranged from 0.02 to 7.34 inches (0.05 to 18.64 cm). In all trials, the head displacement toward the driver side B-pillar was insufficient to cause physical contact.
Shibata, Peggy, Roberts, Julius, Sprague, James, Light, Alyson, Stegemann, Jacob, Meza-Arroyo, Manuel, Capser, Shawn
Seat Performance and Occupant Moving Out of the Shoulder Belt in ABTS (All-Belts-to-Seat) in Rear Impacts2019-01-10314/2/2019
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
Video-Recorded “Looked-but-Failed-to-See” (LBFTS) Accidents in the Junctions of Hong Kong2018-01-50491/18/2019
To determine causation and contributory factors of “looked-but-failed-to-see” (LBFTS) junction accidents in which the driver stated that “I did not see the pedestrian,” in-depth studies of 22 such accidents which had taken place in Hong Kong were conducted. The studied crashes were all video recorded by closed-circuit television (CCTV) cameras and/or dashboard cameras. Using the video recordings, these junction accidents were reconstructed at the scenes to determine the drivers’ views of the pedestrians and the sequence of events leading up to each accident. The results of the reconstructions and the police investigations, as well as the testimony of the drivers, were analyzed to identify causation and contributing factors of each accident. Attention error/visual search strategy (41%) and misjudgments of drivers (18%) remain the dominant cause of LBFTS crashes. However, it was found that eight crashes (36%) were attributed to the physical obstructions caused by the A-pillars of the vehicles, with the obscuration of the pedestrians being the major contributory factor. This study shows that reconstructions based on video recordings can provide detailed accounts of junction accidents to determine causations and to understand the individual characteristics of each accident. It also reveals A-pillar obscuration to be a cause of such accidents, and this provides a basis for further research on the A-pillar “blind spot.”
Cheng, Yuk Ki, Tam, Cheok Ning, Tao, Chi Hang, Tsang, Cheuk Nam
Comparative Responses of the PIPER 6YO Human Body Model and the Q6 ATD for Simulated Frontal and Lateral ImpactsSC18-22-000611/12/2018
Abstract - Adult and pediatric human body models have focused on developing accurate representation of the human body in terms of anthropometry and kinetics/kinematics in correlation with published PMHS (Post-Mortem Human Subjects) data. This study focuses on comparing the PIPER 6-year-old human body finite element (FE) model with a Q6 FE model to generate comparable metrics. The FE models were simulated in a vehicle environment by positioning them on two different child booster seats with a 3-point lap-shoulder belt for frontal and lateral impacts. The overall kinematic response (head excursion) of the PIPER human body model (HBM) mimics the behavior of the Q6 ATD. However, there is a significant difference in the NIJ values between the PIPER HBM and Q6 ATD (minimum reduction of 67% in PIPER HBM). The head-neck complex of the PIPER is seen to be more flexible (minimum reduction of 12% in neck forces and 64% in neck moments) as compared to the Q6.
Sarfare, Shreyas, Maheshwari, Jalaj, Duong, Nhat, Belwadi, Aditya
AV testing is for DUMMIES18AUTP11_1211/1/2018
Rapid development of automated vehicles is driving ATD innovations, as Humanetics' CEO explains. A few years ago, Chris O'Connor started to notice a common talking point emerging from within the many autonomous vehicle conferences and meetings he was attending. “It seemed that many people in the industry, and those in Congress, were saying: ‘With autonomous cars, we won't have traffic accidents anymore,’” noted O'Connor, the CEO of Humanetics Innovative Solutions, the leading developer of anthropomorphic test devices (ATDs), commonly known as crash-test dummies. “And since there won't be crashes, we will no longer have to worry about occupant safety,” he recalled many pronouncing.
Brooke, Lindsay
Validation of Crush Energy Calculation Methods for Use in Accident Reconstructions by Finite Element Analysis09-06-02-000910/4/2018
The crush energy is a key parameter to determine the delta-V in accident reconstructions. Since an accurate car crush profile can be obtained from 3D scanners, this research aims at validating the methods currently used in calculating crush energy from a crush profile. For this validation, a finite element (FE) car model was analyzed using various types of impact conditions to investigate the theory of energy-based accident reconstruction. Two methods exist to calculate the crush energy: the work based on the barrier force and the work based on force calculated by the vehicle acceleration times the vehicle mass. We show that the crush energy calculated from the barrier force was substantially larger than the internal energy calculated from the FE model. Whereas the crush energy calculated from the vehicle acceleration was comparable to the internal energy of the FE model. In full frontal impact simulations, the energy of approach factor (EAF) has a linear relation with the residual crush, which had been validated in previous experimental studies. In our study using FE analysis, we found that the slope of EAF versus the residual crush was comparable with that of the dynamic crush energy versus the dynamic crush for crashes at 55 km/h. Using this slope and the residual crush from a 55 km/h impact test, the slope and the intercept of the EAF vs. residual crush can be determined using only one crash test. A database of the slopes and the intercepts was made using Japan New Car Assessment Program (JNCAP) tests. In offset impact simulations, the crush energy calculated from the crush profile agreed with the internal energy of the car FE model when at least one front rail was involved. In oblique impacts, the correction factor for crush energy is not necessary within 20 degrees of principal direction of force of the car’s longitudinal axis.
Numata, Shusuke, Mizuno, Koji, Ito, Daisuke, Okumura, Dai
Autonomous vehicles present passive-safety challenges18AUTP10_0810/1/2018
Reclined and rotated seating positions are commonly depicted for autonomously driven vehicles. But for the Autoliv engineers tasked with developing occupant safety for tomorrow's self-driving vehicles, those previously improbable seating positions dictate innovative new passive safety protections. “Passive safety for autonomous vehicles is a pretty complicated problem to solve, which is why we're starting out with the simplest scenario: a frontal crash with a front occupant in a partial-recline position,” E. Scott Dershem, Autoliv's Vice President of Product Development, said in an interview with Automotive Engineering at the safety supplier's Auburn Hills, Michigan technical center.
Buchholz, Kami
Torsional Fluctuations Consideration while Design of Synchro Rings2018-01-18239/10/2018
In today’s manual transmissions of car, gearshift system requires high performance with particular emphasis on low effort, minimal travel and positive feel. To meet these targets, a high capacity multi cone synchronizers along with higher co-efficient of friction material used for lower gears. The design of synchronizer with these specifications is influenced by torsional fluctuations from engine. Excessive torsional vibrations leads to wobbling of synchro rings within the peripheral clearances with surrounding parts. Wobbling leads to abrasion wear of frictional area of synchro ring causing grating or crashing noise of gears during shifting. This paper presents the optimization of the multiple cone synchronizer design exposed to excessive torsional vibrations and validation of the same on test bench during development stage instead vehicle level validation.
Tawhare, Nitin, Aswale, Dhananjay, Ponkshe, Makarand
Driver Risk Perception Model under Critical Cut-In Scenarios2018-01-16268/7/2018
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 indicated brake strength. Brake pressure change rate (BPCR) and longitudinal jerk (derivative of acceleration) at initial brake time indicated brake speed. Analytic Hierarchy Process and Fuzzy Comprehensive Evaluation Method were adopted to obtain an integrated subjective risk perception indicator D. Critical cases were divided into 3 groups by distance of within 5 m, from 5 to 15 m and over 15 m. Within the distance of 5 m, D was linear with 1/THW. Within the distance of from 5 to 15 m, D was linear with 1/TTC. Within the distance of over 15 m, both 1/THW and 1/TTC have linear relationship with D.
Ma, Xuehan, Feng, Zhiwei, Zhu, Xichan, Ma, Zhixiong
Passenger Car 25% Overlapping Collision Accident Study Base on CIDAS2018-01-15958/7/2018
With the development of vehicle technologies, vehicle safety is much better than before, many companies put research focus on harder accident scenarios. The 25% overlapping collision is considered as one type of most dangerous collision, this paper study this type accidents base on CIDAS database. Paper showed 7 scenarios appeared frequency in China, 11, 12, 1 o’clock are main impact direction. High way and freeway are the main places, and the head, thorax and lower extremities were the main sites of injury.
Li, Xudong, Lin, Miao, Lian, Xiaowei, Cui, Fujun
Predictive Estimation of Side Pole Impact Dummy Response Based on Linear Impactor SAB Performance2018-01-50186/18/2018
This article discusses steps to predictively estimate the responses of Anthropomorphic Test Device (ATD) in a side impact event, based on a Side Airbag (SAB) Force-Deformation (F-D) characteristics derived from the linear impactor test. A critical load management challenge that has been used to assess this predictive response process is the oblique pole impact test - part of the FMVSS 214 protocol. In this scenario, the ATD is assumed to have a free travel until it is stopped by the crushed and stacked up door against the rigid pole. Three critical energy management paths involved to manage the kinetic energy of the ATD at impact are assumed at the onset, namely, the door trim crush, ATD torso loading and most important efficient energy management of the SAB at a controlled force level. The SAB energy management is assumed critical and tied with the final response of the test ATD. In the study being reported, the amount of energy absorbed by the SAB and the reaction force of the SAB are used to predictively estimate the final responses of the test ATD. After robust vehicle components and systems designs for body structure, door trim, friendly interior and effective SAB to ATD coverage are achieved, results from this study show that the F-D response of the SAB is crucial and may be used to predictively estimate the final response of the test ATD. The ability to predictively estimate ATD responses via linear impactor derived SAB F-D at the component level will invariably greatly reduce SAB development time and overall side impact safety development cost. Examples of physical SAB linear impactor test results have been used to demonstrate the effectiveness of this predictive assessment tool in terms of SAB development time.
Uduma, Kalu, Purushothaman, Dipu, Wu, Jianping, Beaudet, Brian, Keshtkar, Hamid
Analysis of Single-Vehicle Accidents in Japan Involving Elderly Drivers09-06-01-00026/5/2018
The Japanese population is aging rapidly, raising the number of traffic accidents involving elderly drivers. In Japan, single-vehicle accidents are a serious problem because they often result in fatalities. We analyzed these accidents by vehicle type, age group, and driving area. To examine the risk of accidents of the elderly drivers, their driving frequency needs to be considered, which is less. Moreover, it is difficult to know the actual distance driven by them. Therefore, in this article, based on the assumption that the number of rear-end collisions is a proxy for the traffic volume, we used the number of such collisions as a control for the driving frequency. It was found that in single-vehicle accidents, elderly drivers were at higher risk than other age groups, especially when driving light motor vehicles (K-type vehicles) in non-urban areas. A possible explanation is the higher frequency with which the elderly drive K-type vehicles in areas where there are few other vehicles on the road.
Morita, Kazumoto, Sekine, Michiaki
Modeling the Effect of Foam Density and Strain Rate on the Compressive Response of Polyurethane Foams05-11-02-00145/8/2018
Due to the high deformability and energy dissipation capacity of polymer foams in compression, they are used in automotive applications to mitigate mechanical impacts. The mechanical response of the foams is strongly affected by their density. Phenomenological relations have been proposed to describe the effect of foam density on their stress-strain response in compression at a fixed loading rate and the effect of loading rate at a fixed foam density. In the present work, these empirical approaches are combined allowing for the dependence of loading rate effect in compression on foam density. The minimum experimental data set for calibration of the proposed model consists of compression test results at two different loading rates of foams with two different densities. Rigid closed-cell polyurethane foams with apparent density in the range of ca. 100 to 300 kg/m3 have been produced and tested in compression up to a ca. 80% engineering strain at low (0.00167 to 0.5 s−1) and intermediate (~102 s−1) strain rates. The model parameters were evaluated from test results of the largest and smallest-density foams at low loading rates, differing by two orders of magnitude. The relative root mean square error of stress prediction for intermediate foam densities was found to range from ca. 6 to 12% at low strain rates and reach up to 34% at the higher strain rate. The proposed approach for modeling of foam behavior is expected to be useful in preliminary design of structural parts with impact mitigation functionality.
Japins, Guntis, Kalnins, Kaspars, Kirpluks, Mikelis, Cabulis, Ugis
Research of Steering Grasping to Take over Driver from System2018-01-10684/3/2018
Lane departure prevention systems are able to detect imminent departure from the road, allowing the driver to apply control to prevent lane departure. These systems possess enormous potential to reduce the number of accidents resulting from road departure, but their effectiveness is highly reliant on their level of acceptance by drivers. The effectiveness of the systems will depend on when they are providing driving assistance, what level of laxness in terms of maintaining contact with the steering wheel is allowed on the part of the driver, and what level of assistance the system provides. This paper will discuss research on the minimum necessary contact and contact strength with the steering wheel on the part of the driver when a lane departure prevention system is in operation. Using a six-axis driving simulator employing an actual vehicle, the research conducted tests involving 22 test subjects, and studied the relationship between the status of the driver’s contact with the steering wheel and vehicle behavior when the system failed. As a result of simulation, when the driver had relinquished steering control and the vehicle was self-steering on the curve, contact of even one finger with the steering wheel made the reaction time faster.
Odate, Shotaro, Fujimaki, Takeshi, Sakamoto, Naohiro
Correlation of “Non-Zero” Speedometer Readings with EDR Data2018-01-05224/3/2018
Observations made during forensic automotive crash investigations have identified instances of non-zero, post-crash speedometer readings and created questions as to the validity of the indicated speed relative to the vehicle speed at impact. Previously published work has addressed many issues related to the reliability of non-zero, post-crash speedometer readings identified in vehicles as well as motorcycles. Much of this work established criteria that related the reliability of the post-crash needle position to the design of the stepper motor that controls the needle. Part of this criteria is related to the static torque associated with the speedometer needle shaft rotation due to outside (crash) forces. The published criteria were evaluated in staged crash tests which investigated the ability to maintain needle position under longitudinal and lateral forces after an electrical power loss. In an effort to extend the science, this paper compares non-zero, post-crash speedometer readings with event data recorder (EDR) data from twenty-one real-world crashes where both non-zero, post-crash speedometer readings and EDR data were available. Results from this study suggest a positive correlation between non-zero speedometer readings and vehicles experiencing both an electrical power loss and a single impact. However, this study also shows a negative correlation between non-zero speedometer readings and vehicles experiencing an electrical power loss and multiple impacts. Eighteen of the twenty-one vehicles had valid pre-crash EDR speeds. Of those eighteen vehicles, the speedometer position and EDR speed were within ±15% for fourteen of the vehicles. The current study also demonstrates that non-zero tachometer readings do not always improve confidence levels of non-zero speedometer readings. While the post-crash needle position may provide a good estimate of the travel speed of the vehicle at the time of power loss, there are numerous other factors which must be considered prior to accepting these readings.
Yannaccone, John R., Kinder, Robert
An Analytical Review and Extension of Two Decades of Research Related to PC-Crash Simulation Software2018-01-05234/3/2018
PC-Crash is a vehicular accident simulation software that is widely used by the accident reconstruction community. The goal of this article is to review the prior literature that has addressed the capabilities of PC-Crash and its accuracy and reliability for various applications (planar collisions, rollovers, and human motion). In addition, this article aims to add additional analysis of the capabilities of PC-Crash for simulating planar collisions and rollovers. Simulation analysis of five planar collisions originally reported and analyzed by Bailey [2000] are reexamined. For all five of these collisions, simulations were obtained with the actual impact speeds that exhibited excellent visual agreement with the physical evidence. These simulations demonstrate that, for each case, the PC-Crash software had the ability to generate a simulation that matched the actual impact speeds and the known physical evidence. Simulation of a full-scale rollover test reported by Asay [2010] is also examined. For this test, we obtained a simulation that exhibited an excellent visual match with the pre-roll tire marks and furrows and in which the vehicle rolled 7 times, just as it did in the actual test. The rest position of the vehicle was well matched, though a portion of the simulated roll trajectory did not match the actual roll trajectory. These areas of additional analysis extend the prior literature.
Rose, Nathan A., Carter, Neal
Influence of Driver Position and Seat Design on Thoracolumbar Loading During Frontal Impacts2018-01-05444/3/2018
Previous research has detailed contributing factors to thoracolumbar compression fracture injury risk during frontal impacts in motorsport drivers utilizing a nearly recumbent driving position (Katsuhara, Takahira, Hayashi, Kitagawa, & Yasuki, 2017; Trammell, Weaver, & Bock, 2006; Troxel, Melvin, Begeman, & Grimm, 2006). This type of injury is very rare for upright seated motorsport drivers. While numerous improvements have been made to the driver restraint system used in the National Association for Stock Car Auto Racing, Incorporated (NASCAR®) since 2000, two instances of lumbar compression fractures have occurred during frontal impacts. Through the use of computation modeling, this study explores the influence of initial driver position and seat ramp design on thoracolumbar loading during frontal impacts. Quasi-static component testing, dynamic component testing, an instrumented driver fit check, a seat ramp angle survey, and sled testing were conducted to provide computational finite element (FE) model inputs and serve as validation tests. Upright magnetic resonance imaging (MRI) was conducted with a driver to visualize vertebral body locations with respect to the driver seat. FE modeling was conducted with the 50th percentile male Hybrid III FE model (Humanetics, Plymouth, MI) to validate a motorsport restraint system model. Sprague and Geers analysis was used to quantify and identify the optimally tuned FE model parameters. A 3-factor latin hypercube (LHD) sample space was created for acceleration magnitude and the principal direction of force (PDOF) about the Z-axis and about the Y-axis across 20 simulations. The Toyota Total Human Model for Safety (THUMS) was then used in four unique seat ramp angles in both slouched and upright postures, for a total of eight THUMS seated configurations. All eight configurations were subjected to the 20 variable values of the LHD sample space for a total of 160 simulations. A FE motorsport restraint system model was developed and validated against empirical component and sled test data. The THUMS was used in the validated motorsport restraint system. As seat ramp angles (SRA) increased, peak axial compressive force of T12, L1 and L2 decreased. For each SRA, the slouched THUMS initial position (TIP), which positioned the ischial tuberosities closer to the seat ramp, produced lower peak axial compressive forces. The peak XY resultant bending moment of T12 and L1 also decreased as SRA increased.
Patalak, John, Davis, Matthew, Gaewsky, James, Stitzel, Joel, Harper, Matthew
A Tailor Welded Blanks Design of Automotive Front Rails by ESL Optimization for Crash Safety and Lightweighting2018-01-01204/3/2018
Utilizing the tailor welded blanks (TWBs) design along with the latest AHSS grades for the front rails on a sedan was studied to reduce the weight of the vehicle and improve the crash safety performance. To find the most efficient material usage, the front rail parts were tailored into multiple blanks with varying thickness. A structural thickness optimization study of the tailored front rails was conducted for IIHS moderate overlap frontal crash, and the tailored blank thickness was set as design variable. The equivalent static loads (ESL) method was adopted for the thickness optimization, which allows many design variables to be optimized simultaneously. The torsion and bending stiffness of the sedan body in prime were set as design constraints, and would not be compromised. The optimal thickness configurations of the TWB designs by ESL optimization suggest that the weight of the frontal rails can be reduced by more than 30% while still maintaining the crash safety performance. These TWB designs were validated by US-NCAP full frontal impact and show similar performance with baseline. A 3rd gen AHSS, NEXMET™1000, was selected on four parts of the front rails to replace the baseline HSLA350. The optimal tailored frontal rail design using NEXMET™1000 grade was obtained through ESL thickness optimization and validated by US-NCAP full frontal impact. Compared with HSLA350, the NEXMET™1000 grade offers better crash safety performance with more weight reduction potential. An optimal thickness coefficient is proposed in this study to evaluate the material efficiency of the tailored blanks and the amount of thickness changes required for each blank to reach the most efficient material usage. The optimal TWB thickness configurations for HSLA350 and NEXMET™1000 grades through ESL were evaluated using this optimal thickness coefficient. The critical locations on front rails for crash safety were identified and the amount of thickness changes needed characterized. The tailor welded blanks technology can be implemented in the front rail design to reduce weight and improve crash safety. This optimal thickness coefficient can guide the automotive design for lightweighting.
Liang, Jianyong, Powers, Jonathan, Stevens, Scott
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