Showing papers on "Rear-end collision published in 1998"

Development of a collision avoidance system

Abstract: The analysis of a rear-end collision warning/ avoidance (CW/CA) system algorithm will be presented. The system is designed to meet several criteria: 1. System warnings should result in a minimum load on driver attention. 2. Automatic control of the brakes should not interfere with normal driving operation.

A collision warning algorithm for rear-end collisions

Abstract: The purpose of this paper is to develop an experimentally-based rear end collision warning algorithm for the situation where two vehicles are initially traveling at the same speed in the same direction when the lead vehicle begins to brake. The full variety of initial conditions of vehicular motion are analyzed to determine the proper collision warning algorithm. The analysis shows that knowledge of traveling speed, headway, and lead-vehicle deceleration is sufficient to determine the type of relative motion. This can be coupled with warning logic and principles of vehicle dynamics to produce warning algorithms. An approach to warning implementation is suggested that avoids the difficult problem of estimating the lead-vehicle deceleration; using instead other measurable quantities such as range and range-rate. For the covering abstract see IRRD E102514.

Seat designs for whiplash injury lessening

Abstract: The purpose of this study is to evaluate the potential for the reduction of occupants neck injuries, so called "whiplash injuries" (whiplash associated disorder), in rear end collisions. Based upon new biomechanical research, an effort was made to design head restraints and seats to help lead to a reduction of such injuries. This resulted in a concept which involves the motion of the head and torso in harmony during a rear end collision. Consequently a newly designed seat based upon this concept is evaluated in low speed rear impact dummy sled tests, and additionally offered in volunteer sled tests using X-ray cinemas conducted by Japan Automobile Research Institute and University of Tsukuba, who investigate the influence of seat characteristics to human head and torso kinematics and cervical vetebra movement to reveal the mechanism of whiplash injuries. As a result, it was found that the motion between head and torso as well as the movement between each cervical vertebra was reduced. (A) For the covering abstract see IRRD E102514.

Identification of pre-crash scenarios for estimating the safety benefits of rear-end collision avoidance systems

Abstract: This paper identifies dynamically-distinct precrash scenarios as a basis for estimating the safety benefits of Intelligent Transportation System (ITS) rear-end collision avoidance systems (CASs). These precrash scenarios constitute a set of hazardous driving situations that occur immediately prior to a rear-end crash. This effort lays the foundation for improved estimates of the safety benefits of rear-end CASs which were produced in a previous study by the National Highway Traffic Safety Administration (NHTSA) of the United States Department of Transportation. This paper identifies ten precrash scenarios from over sixty thousand rear-end crash cases drawn from NHTSA's 1992-1996 General Estimates System (GES) data bases. These scenarios accounted for an average of about 94.1 percent of all police-reported rear-end crashes. In addition, this paper provides a statistical description of these scenarios in terms of maximum injury severity, roadway surface condition, posted speed limit, and light and atmospheric conditions using the 1996 GES data base. For the covering abstract see IRRD E102946.

A comparison study of active head restraints for neck protection in rear-end collisions

Abstract: Neck injuries caused by rear-end collisions have become a major problem in traffic safety over the last two decades, however, surprisingly little effort has been made so far to improve car seat and head rest design. Several studies have shown, that whiplash injuries can be reduced by minimizing the gap between head and head restraint during the first phase of a rear-end impact. On the other hand, the requests for comfort from the car passengers limit the reduction of this distance. Various publications show that generally neither drivers nor passengers are aware of the necessity to adjust current head rests to their head position. The conclusion is, the head rest should either be large enough to protect all occupants or should be automatically adjusted to protect all occupant sizes. This study shows a comparison of different active head restraint concepts, which guarantee a reduction of the distance between head and head rest during a rear-end collision. In addition the size of the head rest is enlarged. Different concepts were validated by sled tests using Hybrid-III Dummies equipped with the newly developed TRID-neck. Also volunteer tests were performed to prove the effectiveness of the new concepts. (A) For the covering abstract see IRRD E102514.

In-depth investigation and reconstruction of an air bag induced child fatality

Abstract: A minor rear-end collision resulted in the death of a four-year old child, occupying the right-front seat of the striking vehicle. The child was restrained by means of a lap belt, the shoulder portion of the belt system having been placed behind the child's back. The child was leaning forward, when the vehicle's brakes were suddenly applied, just prior to the crash. The passenger air bag deployed and the child sustained fatal neck injuries. The case incident was subject to an in-depth collision investigation. Physical evidence associated with the crash, combined with witness statements, and medical data, enabled the vehicle dynamics, occupant kinematics, and occupant contract points to be accurately determined. The collision was subsequently reconstructed using an instrumented child dummy and static deployment of exemplar air bags. A car to rigid barrier dynamic test was also conducted. High-speed film and video recordings of the tests revealed that even minor changes in the position of the dummy had considerable effect on the post-deployment kinematics. Combining the experience gained from a number of such trials, the real-world event was successfully reconstructed in the laboratory. (A) For the covering abstract see IRRD E102514.

Light vehicle forward-looking, rear-end collision warning system performance guidelines

Abstract: This document presents performance guidelines for the design and development of forward looking, rear-end, collision warning systems to improve vehicular safety by eliminating or mitigating vehicular rear-end collisions through driver notification or warning. All aspects of performance are addressed including general system requirements, driver/vehicle interface methodology, collision dynamics, standardized testing and estimation of associated benefits. These guidelines are intended to be used by manufacturers and developers of vehicular based forward-looking, rear-end collision warning systems as a tool to: 1) standardize system requirements, 2) standardize driver interface and control among systems developed by different manufacturers and, 3) standardize testing to be used in verifying proper system operation.

Developing experimental cervical dummy models for testing low-speed rear-end collisions

Abstract: In recent years, many studies have been made in the biomechanical and other fields, on, "whiplash" or cervical vertical sprain which is on type of injury sustained by vehicle occupants in low-speed rear-end collisions. This paper describes a cervical analysis of whiplash occurring in the lower rear-end collision. In particular, it describes the use of a more humanized biomechanical cervical model to analyze cervical behavior in low rear-end collisions. The results of tests with this model were verified on the TRID-II Neck and the Hybrid-III Neck models. (A) For the covering abstract see IRRD E102514.

Studies of Vehicle Collisions - A Documentation of the Simulation Codes: SMAC (Simulation Model of Automobile Collisions) Update 1

Abstract: This document describes part of the work conducted under MOU252 and MOU324, related to the studies of vehicle collisions in vehicle-following operations. This working paper is a detailed documentation of a computer program that is the core element of the simulation tools for vehicle collision dynamics. The program, SMAC (Simulation Model of Automobile Collisions), and its PC-platform version EDSMAC have been used extensively in recent work at PATH to investigate the consequences of vehicle collisions and the effects of vehicle-following parameters on collisions. A copy of the source codes of SMAC was obtained from the University of Michigan Transportation Research Institute (UMTRI). Revisions to the program were made to insert the option of exercising feedback control in collision situations. After these revisions, control algorithms can now be tested in crash scenarios to examine the feasibility and effectiveness of vehicle control in emergency conditions. The structure of the program was outlined in this report with descriptions of the major subroutines. The added options for implementing user-specified steering inputs and feedback controllers were explained in details. An example input file for running the computer program was also provided to illustrate the formats and contents of input parameters. This working report provides a concise and essential documentation for the computer program. KEY WORDS Vehicle Collisions Simulation of Vehicle Crashes Vehicle Control in Collisions Advanced Vehicle Control Systems

Rear-end collision warning device and distance between cars display method

Abstract: PROBLEM TO BE SOLVED: To prevent a rear-end collision accident while generating an accident preventive alarm by checking the reaction of a driver to the fact that distance between cars becomes short and deciding whether or not the driver has done a series of due operations. SOLUTION: When an operation starts, a distance between cars measuring instrument 1 measures the distance to a precedent travel vehicle. At this time, the distance between cars is, for example, 22m. A microcomputer 2 reads in a signal from an operation member 4 linked with an accelerator pedal 3 and stores its value in a memory. Then when the distance between cars veries to <=20m which is predetermined with respect to the measured distance between cars of 22m, the microcomputer 2 reads in an output signal value from the operation member 4. Then the microcomputer 2 compares the stored output signal value from the operation member 4 with the current output signal value and when it judges that a proper measure such as release of the accelerator pedal 3 is not taken although the vehicle distance varies, driver's attention is attracted by an alarm unit 10.

Safety rear underride guards with an optional reverse impact braking system

Abstract: This paper describes the Safe-T-Bar and Sens-N-Stop, two products aimed at reducing personal injury and damage resulting from rear impacts. The Safe-T-Bar is a rear underride protection guard. It can be fitted to all vehicle types, including straight trucks and semi-trailers, up to the maximum gross vehicle weight. There are two versions of the guard, one incorporating rubber springs, the other friction plates. Collision damage to light vehicles occurring at average speeds is radically reduced or in some instances entirely eliminated. Both versions of the Safe-T-Bar have been laboratory tested. The rubber spring version meets EEC Directives e11-011 and e11-013. The friction plate version fully complies with the United States Federal Motor Vehicle Safety Standards FMVSS 223 and FMVSS 224. Sens-N-Stop is an automatic impact-sensing and brake-activating system for reversing vehicles for use in conjunction with the rubber spring version of the Safe-T-Bar. Immediately the beam comes into contact with an obstruction the vehicle brakes are applied. (A) For the covering abstract see IRRD E102514.

Truck crashes in Western Australia 1988 - 1992

Abstract: The purpose of this study was to explore the relevant literature and available data on truck crashes for Western Australia. The review revealed that a number of features of crashes involving trucks distinguish them from crashes involving other vehicles. Data on truck crashes in Western Australia were obtained for the years 1988-1992 from the Road Injury Database. Rear end crashes, crashes involving parked trucks, road train crashes, single vehicle crashes, and the involvement of fatigue in truck crashes, were considered in detail. The findings corroborate the main findings of other researchers who have been interested in truck crashes and add to what is known of truck crashes in Western Australia. The study concluded that crashes in rigid trucks predominate in the Perth region whereas crashes in articulated trucks predominate in the rural and remote region, reflecting differences in the use of different types of trucks in these areas. The rate of crash involvement per 100 million vehicle kilometres travelled outside of Perth increased with the number of trailers in use. Rear end crashes were the most common type of truck crash and in most cases the truck was the colliding vehicle. Single vehicle crashes tended to occur in the rural and remote regions, as did road train crashes. These were associated with a high risk of injury to truck drivers. Fatigue was associated with 20 percent of road train crashes and 17 percent of single vehicle crashes. Fatigue related crashes tended to occur at night, to be related to alcohol and vehicle factors and to occur in the rural and remote regions. The report recommends a review of truck braking systems, truck operations and schedules, and truck construction and stability. A need for practical restraint systems for truck occupants was also identified, as was the need to investigate the high risk of fatality amongst truck drivers involved in road train casualty crashes. (a)