Browse Topic: Rear-end crashes

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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
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
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
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
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
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
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
2021-12-29.TEST Design and Implementation of Adaptive Range LIDAR System (ARLS) for Autonomous Braking Assistance at High Speeds in Automobiles2018-01-00404/3/2018
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 braking circuitry, or in some vehicles, by providing feedback to the Electronic Brakeforce Distribution Systems. Also, since the brake effort curve is dynamic with respect to time, rigorous braking is not imposed on the passenger, and that the retardation is smooth and well distributed in time.
Mishra, Jainendra
Frontal, Lateral, and Free-Operation Impacts of Amusement Bumper Cars: Vehicle Kinematics and Occupant Kinematics2018-01-05434/3/2018
This study conducted a series of rear-impact, side-impact, barrier, and free-operation collisions using a bumper car ride at an active amusement park. Two conditions were studied: staged and free operation. Each staged test included a bullet (impacting) vehicle operated by a rider and a target (impacted) static vehicle or structure. Impact configurations of frontal collisions of the bullet vehicle into the rear and side of a target vehicle were consistent with the existing literature. The free operation condition involved collisions which were not pre-determined, and operators may not have been prepared for collision timing, magnitude, and direction. Results demonstrated high repeatability for vehicle parameters, such as impact velocity, change in velocity, and peak acceleration. Peak changes in velocity during vehicle-to-vehicle collisions were 2.2-2.5 m/s (8-8.9 km/hr; 5-5.5 mph) for the target vehicle and 1.6-1.8 m/s (5.6-6.4 km/hr; 3.5-4 mph) for the bullet vehicle, while those during vehicle-to-retaining barrier collisions were approximately 3.6 m/s (13 km/hr; 8 mph). Coefficients of restitution and overall vehicle and occupant kinematics were similar to prior bumper car studies, and collision magnitudes were similar in the free-operation test to the staged, single-axis collisions. Bumper cars present a model environment to study vehicle and occupant kinematics in vehicle collisions that are within human tolerance and include aware but possibly unprepared occupants. This is relevant to establishing occupant kinematics in and limits to autonomous vehicle emergency handling maneuvers.
Bussone, William R., Moore, Tara, Locey, Caitlin, Cargill, Robert
Plug-in hybrid brings Honda into sharper Clarity18AUTP02_082/1/2018
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
SUPPLIER EYE17AUTP11_0711/1/2017
Facing the new disruptors Industry leaders remain so by staying ahead of the next ‘big’ trend. They view emerging shifts in business and technology as opportunities, regardless of the disruption such trends portend. Even when faced with unexpected (i.e., a natural disaster) or expected (global regulatory) shifts, suppliers must be agile and decisive. Ignorance of disruption is not an excuse. Recent history is littered with examples of the swift exit of key technologies that were once the lifeblood of many suppliers. Sparkplug wires, incandescent bulbs, mechanical throttle control-the list is long indeed. In many cases, the decline was signaled well in advance and took several vehicle cycles to unfold-allowing those impacted to integrate new capabilities, find partners or divest. Other times, the decline was rapid and resulted in hard decisions with few alternatives.
Robinet, Michael
Activation Timing of a Collision Avoidance System with V2V Communication2017-01-00393/28/2017
A vehicle-to-vehicle communication system (V2V) sends and receives vehicle information by wireless communication and assists safe driving. The present study investigated the activation timings of collision information support, collision caution support, and collision warning support provided by a V2V in an experiment using a driving simulator for four situations of (1) assistance in braking, (2) assistance in accelerating, (3) assistance in making a right turn, and (4) assistance in making a left turn at a blind intersection. The four situations are common scenarios of traffic accidents in Japan. Safety margins for collision information support and collision warning support were the time required for the driver to fully apply the brake pedal, while the safety margin for collision caution support was the time required for the driver to begin applying the brake pedal. The study investigated the effects of adding safety margins to standard activation timings. The standard activation timings referred to activation timings defined by V2V guidelines of the Japanese Ministry of Land, Infrastructure, Transport and Tourism. The effects of new activation timings were investigated in the experiment. Objective (based on the use of the accelerator and braking pedals) and subjective evaluations were made of the activation timings. As result, in the case of collision warning support, the appropriate activation timing of V2V is 2.0 s in all experimental conditions. The timing of 2.0 s means that the safety margin is added twice to the standard activation timing. The collision caution support has appropriate activation timing if the safety margin is added once to the standard activation timing under several experimental conditions. In the case of collision information support, the appropriate activation timing was the addition of one safety margin to the standard activation timing in all experimental conditions.
Hirose, Toshiya, Ohtsuka, Yasufumi, Gokan, Masato
Accuracy of the Momentum Energy Restitution Method for Offset Inline Minor Rear-End Impacts2017-01-14253/28/2017
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 bullet vehicle’s impact speed. An overlap of greater than 15.2 cm between the vehicle impacting surfaces allowed for complete collisions and transfer of momentum relative to the bullet vehicle’s impact speed. The profile and composition of each vehicle’s impact surface also contributed to complete vs. incomplete collisions. With individual vehicle damage documented before and after each test, application of a modified MER method, which accounts for impacts where measurable crush damage does not occur, was performed based on the measured damage to theoretically calculate each vehicle’s ΔV. The calculated results utilizing the modified MER method were then compared to the test vehicle acceleration traces which were integrated for determination of each test vehicle’s actual ΔV. Comparison of the calculated vs. actual data indicated a high accuracy of prediction (i.e., 1.4 - 33.2% error) for a vehicle ΔV greater than 0.8 m/s via the modified MER method with a vehicle overlap greater than 15.2 cm. When vehicle overlaps were less than 15.2 cm, a sideswipe aspect was introduced and an over calculation (i.e., 202.0 - 844.5 % error) of vehicle ΔV occurred.
Jones, Brian, Calabro, Michael, Brink, Justin, Swinford, Scott
Method to Optimize Key Parameters and Effectiveness Evaluation of the AEB System Based on Rear-End Collision Accidents2017-01-01123/28/2017
Rear-end accident is one of the most important collision modes in China, which often leads to severe accident consequences due to the high collision velocity. Autonomous Emergency Braking (AEB) system could perform emergency brake automatically in dangerous situation and mitigate the consequence. This study focused on the analysis of the rear-end accidents in China in order to discuss about the parameters of Time–to-Collision (TTC) and the comprehensive evaluation of typical AEB. A sample of 84 accidents was in-depth investigated and reconstructed, providing a comprehensive set of data describing the pre-crash matrix. Each accident in this sample is modeled numerically by the simulation tool PC-Crash. In parallel, a model representing the function of an AEB system has been established. This AEB system applies partial braking when the TTC ≤ TTC1 and full braking when the TTC ≤ TTC2. Lastly, the AEB system’s model is coupled to the kinematic of the vehicle in simulation for virtual trajectories preceding the collision point to evaluate the potential effectiveness of different combinations of TTC according to the collision velocity reduction effectiveness and the excessive avoidance performance. After the simulations of 4284 run with 51 combination of the parameters based on 84 accidents, the results show that among the four desirable combinations, TTC1 = 1.0 s and TTC2 = 0.6 s is suitable for collision avoidance while TTC1 = 0.9 s and TTC2 = 0.5 s has satisfactory excessive collision avoidance.
Zhao, Mingming, Wang, Hongyan, Chen, Junyi, Xu, Xiao, He, Yutong
Collision Deformation ClassificationJ224_201702 (Historical)2/23/2017
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 characters describe the deformation detail concerning the direction, location, size of the area, and extent which, combined together, form a descriptive composite of the vehicle damage. The individual character positions are referred to by column number for identification and computer storage compatibility as illustrated in Figure 1. The definition of each classification is provided in subsequent sections. An Appendix is also provided to assist in application and interpretation.
Data Collection and Archiving Standards Committee
Accident Scenarios on Indian Roads: A Study of Driver Behaviour and Road Infrastructure, based on data collected by ADAC2017-26-00021/10/2017
Most of the time in motor vehicle accidents, the driver of the vehicle (especially driver of the larger vehicle in case of collision involving multiple vehicles) is held responsible for rash and negligent driving. But in-depth study and statistics, points out several external or environmental factors playing crucial role in these unfortunate incidents. In some cases these factors directly influence an accident/crash and in some cases these factors influence the behavior pattern of the driver, which increases risk of unsafe practices. Based on the real time data collected by ADAC on the Gurgaon - Jaipur Stretch of NH-8 and others parts of India, some of the factors that directly or indirectly influences the drivers behaviour, are illustrated in this paper.
Padhy, Sitikantha, Agrawal, Pradeep, Yadav, Yoginder
Ambulance Litter Integrity, Retention, and Patient RestraintJ3027_201611 (Historical)11/1/2016
This SAE Recommended Practice describes the testing procedures required to evaluate the integrity of a ground ambulance-based patient litter, litter retention system, and patient restraint when exposed to a frontal, side or rear impact. Its purpose is to provide litter manufacturers, ambulance builders, and end-users with testing procedures and, where appropriate, acceptance criteria that, to a great extent ensures the patient litter, litter retention system, and patient restraint utilizes a similar dynamic performance test methodology to that which is applied to other vehicle seating and occupant restraint systems. Descriptions of the test set-up, test instrumentation, photographic/video coverage, test fixture, and performance metrics are included.
Truck Crashworthiness Committee
Occupant Restraint and Equipment Mounting Integrity - Rear Impact Ambulance Patient CompartmentJ3044_201608 (Historical)8/17/2016
This SAE Recommended Practice describes the test procedures for conducting rear impact occupant restraint and equipment mounting integrity tests for ambulance patient compartment applications. Its purpose is to describe crash pulse characteristics and establish recommended test procedures that will standardize restraint system and equipment mount testing for ambulances. Descriptions of the test set-up, test instrumentation, photographic/video coverage, and the test fixtures are included.
Truck Crashworthiness Committee
Comparison of the Accuracy and Sensitivity of Generation 1, 2 and 3 Toyota Event Data Recorders in Low-Speed Collisions2016-01-14944/5/2016
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 characteristics of the Generation 3 EDRs. This study extends the understanding of how Toyota EDRs respond in low speed collisions with various collision parameters.
Xing, Peter, Lee, Felix, Flynn, Thomas, Wilkinson, Craig, Siegmund, Gunter
Study on TTC Distribution when Approaching a Lead Vehicle2016-01-14524/5/2016
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
Relationship Between Driver Eyes-Off-Road Interval and Hazard Detection Performance Under Automated Driving2016-01-14244/5/2016
Partially automated driving involves the relinquishment of longitudinal and/or latitudinal control to the vehicle. Partially automated systems, however, are fallible and require driver oversight to avoid all road hazards. Researchers have expressed concern that automation promotes extended eyes-off-road (EOR) behavior that may lead to a loss of situational awareness (SA), degrading a driver’s ability to detect hazards and make necessary overrides. A potential countermeasure to visual inattention is the orientation of the driver’s glances towards potential hazards via cuing. This method is based on the assumption that drivers are able to rapidly identify hazards once their attention is drawn to the area of interest regardless of preceding EOR duration. This work examined this assumption in a simulated automated driving context by projecting hazardous and nonhazardous road scenes to a participant while sitting in a stationary vehicle. Participants engaged in visual-based secondary tasks of various lengths before being exposed to either a hazardous or nonhazardous road scene. Drivers were asked to press a hand-held button as soon as a hazard was detected. Results showed that EOR duration did not influence detection rates or reaction time to imminent hazards. These findings suggest that imminent forward hazards in drivers’ field of view automatically capture drivers’ attention in a manner that does not involve “higher-level” SA processes. Effectiveness of forward cuing in avoiding imminent hazards in a partially automated driving context is not moderated by prior EOR duration.
Glaser, Yi G., Llaneras, Robert E., Glaser, Daniel S., Green, Charles A.
Crashworthiness Design of Automotive Body in White using Topology Optimization2016-01-15354/5/2016
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 process. The results provide a conceptual design which emphasizes the most efficient load paths and could be served as an effective guidance to the next-step BIW detailed design.
Tian, Linli, Gao, Yunkai
A Study on Car Following and Cognitive Ability of Elderly Drivers by Using Driving Simulator2016-01-17373/27/2016
The world is aging rapidly. Many countries can already be categorized as aging or aged societies while a few are becoming super-aged societies. In Thailand as well as in other countries, traffic accidents caused by elderly drivers will continue to rise as a significant percentage of elderly people still prefer to drive. Accidents may be prevented with driving tests and screening methods for elderly drivers. However, it is also necessary to understand the effect of aging on driving ability. With this understanding, driver training, driver assistant systems, and improvements on infrastructure may be designed accordingly. Among various physical changes, cognitive ability of the brain is one of the most significant factors affecting driving ability. In this paper, correlation between various cognitive functions of the brain and car following skill of drivers are considered. Car following skill was chosen because rear-end collisions are some of the most frequent type of accidents in Thailand. Car following skill can be measured objectively by using time headway. Furthermore, car following experiments can be studied reproducibly and safely on a driving simulator. Correlations of car following measurements and various cognitive functions measured with CANTAB software were calculated. It was found that Visuoconstructional-perceptual ability, Executive function, and Complex attention have moderate correlation with the time headway, especially at higher speed.
Ngernsukphaiboon, Thitsadee, Chantranuwathana, Sunhapos, Noomwongs, Nuksit, Sripakagorn, Angkee, Hemrungrojn MD, Solaphat
Vertical Occupant Loading in Car Crashes; Test Methods and Countermeasures2015-01-14594/14/2015
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 seat designs are compared. The modified seat concept includes a deformation element which is built into the rear part of the seat connection to the seat frame. The deformation element allows for a controlled deformation of up to 25 mm. The space under the seat is cleared to allow for total occupant movement up to 150 mm. During this movement, energy is absorbed by the deformation element as well as the springs and seat cushion material. Compared to the reference production seat, the dummy pelvis vertical acceleration is reduced by 25-32% in the situations tested in this study.
Jakobsson, Lotta, Björklund, Magnus, Axelson, Anders
Driver Perceived Threat and Behavior in Rear End Collision Avoidance Situations2015-01-14144/14/2015
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 early intervention by the system and delaying the system intervention long enough in order to ensure that the driver will not or is no longer able to intervene. For this purpose the above mentioned study was designed to determine the braking and steering onsets when the subjects start a collision avoidance maneuver in a rear-end collision scenario either by steering or braking. The results show that the driver intervention onsets are much earlier than the physical limits for both steering as well as braking. It can be assumed that the driver would not consider any system intervention beyond these onsets as an override by the system. Within this paper the results presented include data collected within a study conducted to determine braking and steering onsets applied by drivers in order to avoid rear-end collisions. Based on this information the driver perceived threat in potential rear-end collision scenarios using the in-vehicle steering actuator is assessed. In the end the results will be used as baseline data for the development of an autonomous steering collision avoidance system.
Shah, Jitendra, Benmimoun, Mohamed
Moving Rigid Barrier Collision TestsJ972_201503 (Current)3/13/2015
Collision tests are conducted on automotive vehicles to obtain information of value in evaluation of structural integrity and in reducing the risk of occupant injuries. The deformation resulting from a moving rigid barrier impact is more severe at a given speed than that produced by using an actual vehicle, but is more readily reproducible than that occurring during vehicle to vehicle impacts. The purpose of this SAE Recommended Practice is to establish sufficient standardization of such moving barriers and moving barrier collision methods so that results of tests conducted at different facilities may be compared.
Impact and Rollover Test Procedures Standards Committee
Occupant Restraint and Equipment Mounting Integrity - Rear Impact System-Level Ambulance Patient CompartmentJ3044_201406 (Historical)6/25/2014
This SAE Recommended Practice describes the test procedures for conducting rear impact occupant restraint and equipment mounting integrity tests for ambulance patient compartment applications. Its purpose is to describe crash pulse characteristics and establish recommended test procedures that will standardize restraint system and equipment mount testing for ambulances. Descriptions of the test set-up, test instrumentation, photographic/video coverage, and the test fixtures are included.
Truck Crashworthiness Committee
New Trial Analysis of Characteristics of Accidents and Traffic Violations by Elderly Drivers in Japan2014-01-91275/9/2014
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 that uses the number of stop sign violations, which are considered to occur with the same probability among age groups, as an indicator of driving frequency in place of accidents in which a driver is hit from behind (rear-end collisions). In the new analysis the risk of causing an accident was judged to be 1.24 times higher in elderly drivers than in the 35-44 year age group. In general, the risk of accidents caused by elderly drivers is estimated to be lower than in the previous study.
Morita, Kazumoto, Sekine, Michiaki
Passenger Car Response to Interaction with Tractor-Trailer Steer Tire Lugs2014-01-04754/1/2014
Performing a reconstruction of sideswipe interactions is difficult due to the lack of permanent crush sustained by the vehicles involved. Previous studies have provided insight into the forces involved in creating various types of damage for vehicle-to-vehicle interactions during a sideswipe interaction. However, these data may not be applicable to the interaction that occurs when a tractor-trailer steer tire is involved. As demonstrated in previous studies, steer tire interaction produces a unique pattern of markings on the struck vehicle by the protruding lugs (wheel stud) of the steer tire. These studies have demonstrated that the pattern of cycloidal marks created by the wheel lugs can be used to calculate the relative speeds of the vehicles. While this is helpful in understanding the relative motion of the vehicles, it does not provide information regarding the forces applied at the point of contact. The purpose of this study is to assess the structural response of passenger cars during a sideswipe event involving a tractor-trailer steer tire. The study consists of quasi-static and dynamic tests performed using a stationary tractor-trailer tire spinning at an equivalent speed of 55 mph. A total of 20 quasi-static tests were performed using 3 separate vehicles by forcing the spinning tire against the side of a stationary vehicle. The force and displacement necessary to cause various levels of damage to the passenger car was measured to develop an understanding of the stiffness response at different locations along the side of the vehicle. A range of contact stiffness was achieved by forcing the tire against areas around the door pillars and at the center of the door panels which produced stiffer and softer responses respectively. A total of 8 dynamic tests were performed by driving the side of the same 3 vehicles against the rotating steer tire. The vehicle acceleration and change in speed (Delta-V) associated with contact were measured. Peak forces during the quasi-static testing ranged from 500 to 2,600 lbs with a range of deflection of 0.5 to 3.6 inches. The data provided by the quasi-static testing can be used to assess the lateral forces applied to passenger vehicles based on the level of damage sustained. The dynamic testing was performed at speeds of 4.5 to 6.5 mph and resulted in peak vehicle accelerations of 0.1 to 1.4 g in the lateral and 0.1 to 0.6 in the forward direction. The patterns created by the wheel studs were similar to those presented in previous studies. The results of the dynamic testing can be used to assess vehicle acceleration based on the severity of the damage observed.
Cormier, Joseph, Freund, Mark "Tony", Bonugli, Enrique, Guzman, Herbert
The Psychological and Accident Reconstruction “Thresholds” of Drivers' Detection of Relative Velocity2014-01-04374/1/2014
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
Two-Dimensional Collision Simulations of Low-Speed Crash Tests2013-01-07934/8/2013
A commercially-available two-dimensional software program, validated to model high speed collisions, was extended to analyze rear-end collisions involving speed changes below 10 miles per hour. Simulation results were compared to the results of several series of published full-scale staged collisions. A total of 84 rear-end crash tests, involving 20 vehicles of different makes and models, were analyzed. Test conditions included free-rolling as well as braked vehicles, and in-line as well as oblique collision configurations. The analysis demonstrates that the simulation model provides accurate and reliable predictions of vehicle delta-V's for rear-end collisions, under aligned and oblique conditions, and with free-rolling and braked conditions for the foam core and piston-equipped bumper types examined. Using baseline crush stiffness data derived from higher speed barrier tests, the model was found to over-predict peak acceleration values, and correspondingly, under-predict collision durations in low speed collisions. In modeling collisions with closing speeds below 15 mph, a proportionate reduction of the baseline stiffness coefficients was found to significantly improve the model's prediction of the crash pulse shape, and the corresponding peak acceleration and duration. The ability of the model to predict vehicle deformation under these crash conditions was not examined. It is intended that this technique be used in modeling real-world collisions in conjunction with a separate closed-form momentum analysis. Subsequent to such a momentum analysis, the current technique can be used to model the vehicle speed changes predicted by momentum, and then to examine time-based aspects of the collision such as the timing of vehicle collisions and/or the acceleration time histories and peak accelerations of the involved vehicles, as well as the effects of vehicle alignment and braking.
Deyerl, Eric, Cheng, Louis, Gatti, Jordan
Impact of Driver's Steer Control on Truck-Trailer Combination when Negotiating NATO Double Lane Change Maneuver2013-01-04044/8/2013
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 impact of Driver's skills and lane change control strategy on DLCM.
Yang, Xiaobo
Lumbar Spine Injuries in Rear Impacts of Different Severities2013-01-02214/8/2013
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) passenger vehicle accidents. Of the 7,500 accidents, approximately 500 (weighted value of 225,000) passengers reported some type of lumbar spine injury. These injuries included strains or sprains to the spine (AIS 1 injuries), fractures and herniations (AIS 2). In particular, we stratify the incidence of lumbar spine injuries to low, medium and high speed rear impact crash severities, and correlate seatback deformation and restraint use to the lumbar injuries. The analysis indicated the small number of reported lumbar injuries associated with rear end collisions were mostly musculoskeletal strains/sprains and a few fractures and herniations. Furthermore, there was no correlation of higher incidence of lumbar injury with increasing delta-V. The results of the analysis agreed with those from low-speed human subject tests and low- to moderate-speed ATD rear end simulations that concluded the lumbar spine is well protected by the seat back for properly seat-belted passengers.
Yang, Nicholas, Lam, Tack, Dainty, David, Lau, Edmund
Using Data from a DriveCam Event Recorder to Reconstruct a Vehicle-to-Vehicle Impact2013-01-07784/8/2013
This paper reports a method for analyzing data from a DriveCam unit to determine impact speeds and velocity changes in vehicle-to-vehicle impacts. A DriveCam unit is an aftermarket, in-vehicle, event-triggered video and data recorder. When the unit senses accelerations over a preset threshold, an event is triggered and the unit records video from two camera views, accelerations along three directions, and the vehicle speed with a GPS sensor. In conducting the research reported in this paper, the authors ran four front-to-rear crash tests with two DriveCam equipped vehicles. For each test, the front of the bullet vehicle impacted the rear of the stationary target vehicle. Each of the test vehicles was impacted in the rear twice - once at a speed of around 10 mph and again at a speed around 25 mph. The accuracy of the DriveCam acceleration data was assessed by comparing it to the data from other in-vehicle instrumentation. We found that, for in-line front-to-rear crashes like those tested in this paper, the video, GPS and acceleration data reported by the DriveCam systems is useful for reconstructing crashes, provided that the reconstructionist accounts for potential limitations in the data.
Rose, Nathan A., Carter, Neal R., Pentecost, David, Bortles, William, Voitel, Tilo
Controlling Vehicle Platoon to Alleviate Shockwave Propagation2013-01-00223/25/2013
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
Characteristics of Accidents and Violations Caused by Elderly Drivers in Japan2013-01-00143/25/2013
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 elderly drivers than in the 35-44 year age group. Looking at each type of accident and violation, it is conjectured that they do not purposely disregard traffic signals or commit stop sign violations, but end up having accidents as a result of simply failing to notice them.
Morita, Kazumoto, Sekine, Michiaki
Representativeness and Weighting Methods of Real Time Accident Data in India2013-26-00221/9/2013
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 about accident causes, accident conditions and consequences are roughly obtained. There is a lack of engineering data in the available reports. To address traffic safety related issues like infrastructure, driving behaviour and benefit of vehicle safety systems more detailed accident data is needed.
Kumaresh, Girikumar, Lich, Thomas, Moennich, Jorg, Georgi, Andreas
Biomechanical Responses of PMHS in Moderate-Speed Rear Impacts and Development of Response Targets for Evaluating the Internal and External Biofidelity of ATDs2012-22-000410/29/2012
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 and angular rate sensors (ARS). A total of fourteen sled tests using eight PMHS (males 175.8 ± 6.2 cm of stature and 78.4 ± 7.2 kg of weight) provided data sets of seven PMHS for both test conditions. The biomechanical responses are described at both speeds, and cervical spine injuries are documented. Biomechanical targets are also created for internal and external biofidelity evaluation of rear impact anthropomorphic test devices (ATDs).
Kang, Yun-Seok, Bolte IV, John H, Moorhouse, Kevin, Donnelly, Bruce, Herriott, Rodney, Mallory, Ann
Evaluation of the Internal and External Biofidelity of Current Rear Impact ATDs to Response Targets Developed from Moderate-Speed Rear Impacts of PMHS2012-22-000510/29/2012
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 an additional tool was introduced and utilized which allows for the biofidelity score to be partitioned into components of amplitude, phase, and shape. For internal biofidelity, the BioRID II and RID3D were more biofidelic than the Hybrid III in the 17 km/h test, and the BioRID II was most biofidelic in the 24 km/h test. For external biofidelity, the BioRID II was most biofidelic in the 17 km/h test, while both the BioRID II and the RID3D were more biofidelic than the Hybrid III in the 24 km/h test. Overall, the BioRID II demonstrated the best biofidelity in both the 17 km/h and 24 km/h tests.
Moorhouse, Kevin, Donnelly, Bruce, Kang, Yun-Seok, Bolte IV, John H, Herriott, Rodney
Analysis of Accident Types for Intersection Install Red Light Cameras2012-01-00794/16/2012
In this paper, the analysis has been made on the effect of the reduction of traffic accident following the installation of the red light camera. The survey was based on 2004 when the red light camera started on 13 signal intersections in 3 areas to analyze the number of accident occurrences for 2003 as pre-installation and 2005 to 2007 as the post-installation. Before and after installing the red light camera at each point, the on-site survey was made at the similar points of installed point and un-installed point, and as a result, the average speed of vehicle, dispersion and signal violation rate would be shown to decline at the installed point compared to the un-installed point compared to the pre-installation of the red light camera for average speed of vehicle, dispersion and signal violation rate. This type of result is attributable to have the influence on the safety improvement of the intersection by reducing the signal violation rate with the difference of speed and running speed known to have great influence to the traffic accidents.
Yoo, Sungjun
Kinematics Validation of Age-Specific Restrained 50 th Percentile Occupant FE Model in Frontal Impact2012-01-05654/16/2012
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 kinematics of the shoulder of the adult occupant model, the shoulder girdle muscles were modeled and incorporated into the models. The full body kinematics of the adult occupant model were validated against published frontal sled test results using post-mortem human subjects (PMHS). The seating position of the model was determined according to the average seating position in the PMHS tests. The frontal impact sled buck model consisted of the seat, knee bolster, footrest and pelvis block. These components were modeled with shell elements and treated as rigid bodies. The occupant restraint system consisted of the shoulder and lap belts, modeled with bar and membrane elements. The trajectories were compared between the model and the average PMHS test results by using the coordinates of the head, the first and eighth thoracic vertebrae, the second and fourth lumbar vertebrae and the pelvis. A published ranking system for the biofidelity was applied to them in order to quantitatively evaluate the appropriateness of the full body kinematics of the adult occupant FE model. Model results include peak displacements of the head, the first and eighth thoracic vertebrae in the X direction of 362 mm at 112 ms, 267mm at 121 ms and 207 mm at 115ms, respectively. The peak displacements of the corresponding body regions in the X direction from the average PMHS test results were 354 mm at 113 ms, 257 mm at 115 ms and 216 mm at 113 ms, respectively. The error was less than 5 % compared with the average PMHS test results. The kinematics of the other points selected from the head to the pelvis on the spine of the model showed agreement with the average PMHS test results as well. In addition, the results of the biofidelity rating obtained by applying the rating system also supported good agreement of most of the kinematic parameters. For the elderly model, the kinematics and the predicted rib fracture were compared with those of the adult model. Little difference was found in the whole body kinematics, while larger deflection was found at the thorax as well as a significant increase in rib fractures, which were assumed to be caused by the lowered body stiffness and tolerance by aging.
Ito, Yuichi, Dokko, Yasuhiro, Motozawa, Yasuki, Mori, Fumie, Ohashi, Kazuki
A Comparison of 3D Model Dynamic Simulation Results with Low-Speed Crash Test Data2012-01-06014/16/2012
Evaluation of vehicle impacts may involve the use of computer simulations. While simulation programs with two-dimensional impact models have been used for decades, more recent three-dimensional impact models have been developed. This research compares DyMESH, the three-dimensional vehicle impact model in HVE-SIMON, with full-scale vehicle crash tests involving low-speed rear impacts. Exponent Failure Analysis Associates (Phoenix, Arizona) conducted rear impact research involving two virtually identical 1983 Nissan Pulsar NX 2-door vehicles. One vehicle was stationary, while the second vehicle impacted the rear of the first vehicle in an aligned configuration. Tests were run at impact speeds ranging from 5 to 20 MPH. Tri-axial accelerometers were positioned in both vehicles and vehicle acceleration and velocity responses were recorded. SIMON-DyMESH was used to simulate these impact tests. DyMESH utilizes a mesh shell determined by the three-dimensional geometry of the vehicle. Crush stiffness coefficients used by DyMESH may not directly translate from A and B stiffness values used in two-dimensional impact simulation programs. Therefore, a method for calculating crush stiffness coefficients for use in three-dimensional impact models using barrier crash test data was applied. SIMON-DyMESH simulated acceleration pulses and velocity changes were compared to the crash test data. The effect of adjusting a simulation input parameter related to the coefficient of restitution was evaluated.
Fittanto, Daniel, Allen Rodowicz, Kathleen
Investigation on Occupant Ejection in High Severity Rear Impact based on Post Mortem Human Subject Sled Tests2011-22-000511/7/2011
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) conducted in a laboratory environment and resulting in ejection. This paper describes a total of 10 sled tests conducted on 3 belted PMHS using a simplified seat design composed of rigid plates assembled such that the angular and linear stiffness of the seatback (including the foam) was modeled. The initial angular position and the range of motion of the seatback, the size of the PMHS, the slack length of the seatbelt, the angular stiffness of the seatback, and the use of headrest were varied in the test matrix while the pulse was kept constant (triangular acceleration with a peak of 17 G at 30 ms and a duration of 95 ms). In the test series, the tests were not run randomly but the likelihood of occupant ejection was increased systematically until ejection occurred. PMHS seat ejection was observed only for the 95th percentile, initially positioned with a seatback angle relative to the vertical equal to 22°, a range of seatback angular motion equal to 44° and no headrest. Repeating the test under the same conditions but with the pretensioner fired did not prevent the ejection. In addition, the 50th percentile belted specimen was not observed to sustain rearward seat ejection under realistic conditions including the use of headrest.
Petit, Philippe, Luet, Carole, Potier, Pascal, Vallancien, Guy
Development of a Duration Threshold for Modulating Evoked Neuronal Responses After Nerve Root Compression Injury2011-22-000111/7/2011
Cervical nerve roots are susceptible to compression injuries of various durations. The duration of an applied compression has been shown to contribute to both the onset of persistent pain and also the degree of spinal cellular and molecular responses related to nociception. This study investigated the relationship between peripherally evoked activity in spinal cord neurons during a root compression and the resulting development of axonal damage. Electrically evoked spikes were measured in the spinal cord as a function of time during and after (post-compression) a 15 minute compression of the C7 nerve root. Compression to the root significantly (p=0.035) reduced the number of spikes that were evoked over time relative to sham. The critical time for compression to maximally reduce evoked spikes was 6.6±3.0 minutes. A second study measured the post-compression evoked neuronal activity following compression applied for a shorter, sub-threshold time (three minutes). Ten minutes after compression was removed, the discharge rate remained significantly (p=0.018) less than baseline by 58±25% relative to sham after the 15 minute compression, but returned to within 3±33% of baseline after the three minute compression. Axonal damage was evident in the nerve root at day seven after nerve root compression only after a 15 minute compression. These studies demonstrate that even a transient mechanical insult to the nerve root is sufficient to induce sustained neuronal dysfunction and axonal pathology associated with pain, and results provide support that such minor neural tissue traumas can actually induce long-lasting functional deficits.
Nicholson, Kristen J., Quindlen, Julia C., Winkelstein, Beth A.
On driver distraction, the ‘eyes’ have it11AEID0621_016/21/2011
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
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