Rear-end collision

About: Rear-end collision is a research topic. Over the lifetime, 618 publications have been published within this topic receiving 5666 citations. The topic is also known as: shunt.

The Potential Value of a Front-to-Rear-End Collision Warning System Based on Factors of Driver Behavior, Visual Perception and Brake Reaction Time

Abstract: The potential value of a front-to-rear-end collision warning system based on factors of driver behavior, visual perception and brake reaction time is examined in this paperTwenty-four percent of all motor vehicle crashes involving two or more vehicles are front-to-rear-end collisions These collisions demonstrate that several driver performance factors are common The literature indicates that drivers use the relative size and the visual angle of the vehicle ahead when making judgments regarding depth In addition, drivers often have difficulty gauging velocity differences and depth cues between themselves and the vehicle they are following Finally, drivers often follow at distances that are closer than brake-reaction time permits for accident avoidance It is apparent that the comfort level of close following behavior increases over time due to the rarity of consequences Experience also teaches drivers that the vehicle in front does not suddenly slow down very oftenOn the basis of these driver behavi

PRE-SAFE® in rear-end collision situations

Abstract: In 2002 the first bridge between active and passive automotive safety was built. The MY03 MercedesBenz S-Class was the first car in the world that implemented preventive measures for occupant protection which took effect before the actual impact occurred. Meanwhile the name “MercedesBenz PRE-SAFE ® System” became well known. Since then many other cars from various car manufacturers have adopted this principle of a “natural protection reflex”. In order to detect dangerous situations or upcoming accidents, various sensor systems are being used in these cars today. In addition to sensors that keep an eye on the driving dynamics or on the driver reaction, the use of radar sensors or cameras has become common during the past few years. Almost all of those systems observe the area in front of the car and therefore address situations with an increased risk for a frontal impact. Very few systems presented up to now are capable to “look” backwards and thus detect an imminent rear impact. This paper presents the Mercedes-Benz approach to integrate this type of accident into the PRE-SAFE ® System. The paper covers the issue of detecting collision objects on the basis of radar data. And it presents a cascade of precautionary actions that can improve occupant protection in rear-end accident situations. In particular, the purpose and benefit of a preventive increase of brake pressure is discussed, as well as taking into account further actuators such as a reversible seat belt pretensioner or an active headrest. In order to substantiate the benefit of such a system several evaluation charts on the reduction of the impact severity, the dummy loads and the estimated risk of whiplash injuries are included. Based on accident simulations there are also evaluations about the reduction of the “accident radius” and thus the risk of a secondary impact. Finally the question of an appropriate electronic architecture for such an integral safety system is touched upon.

New approach of accident benefit analysis for rear end collision avoidance and mitigation systems

Abstract: In Germany approximately 12% of all accidents with persons injured and approximately 20% of all material damage accidents are caused by cars in rear end collisions. As a consequence, Bosch is introducing collision avoidance and mitigation systems for rear impact scenarios. Warning, brake support, and autonomous emergency braking are part of Bosch's Advanced Emergency Braking Systems which address such accidents. This study determines the benefit of these assistance and safety systems and estimates the collision avoidance capability considering the driver's behavior. By analyzing representative accidents with injuries from the GIDAS (German In-Depth Accident Study) database, a high potential for collision warning and avoidance systems was determined. For the first time in such a study, this analysis considers the effects of different driver reactions due to warning, braking support, or autonomous braking with respect to the possible driver behavior. For this, a calculation method was developed and used for evaluating the accidents automatically. Both accident avoidance and average speed reduction was determined for different driver types, warning strategies and applications. From the results, an avoidance ratio of 38% for Predictive Collision Warning up to 72% for Automatic Emergency Braking, of all rear-end accidents can be expected for a realistic driver. Therefore it is estimated that 3 out of 4 accidents with severe injuries could be avoided based on the Emergency Brake Assist function and assuming a 100% installation rate. The potential to reduce collision speed in non avoided accidents is calculated on an average basis and is determined to be between 25% and 55% for the realistic driver. The results in the analyses show the high efficiency of the Bosch AEBS functions in avoiding accidents or mitigating injuries by reducing collision speed and should encourage the introduction of Advanced Emergency Braking Systems across a wide range. The full text of this paper may be found at: http://www-nrd.nhtsa.dot.gov/pdf/esv/esv21/09-0281.pdf For the covering abstract see ITRD E145407.

Time-to-collision judgements: visual and spatio-temporal factors

Abstract: A fundamental aspect in driving is predicting critical events in the near future. A driver on a collision course, for example, has to accurately evaluate how close s/he is to the impending collision in order to brake or swerve at the right time. In other words, s/he has to judge time-to-collision (TTC), which refers to the time that remains before reaching an obstacle, and thus to the time available for taking action. TTC is considered to be a crucial parameter in controlling avoidance behaviour. TTC is also likely to be involved in more complex judgement tasks such as overtaking or left-turn manoeuvres, where the driver has to determine whether there is enough time for the planned action. The underlying concept of temporal action control is being used increasingly often in the study of driving behaviour, which addresses the anticipatory aspects of actions such as braking, trajectory control, car following, traffic merging decisions, curve taking, stop-or-go decisions at intersections, and so on. Various equivalent terms have been employed, depending on the situation under investigation, including 'time-to-contact', 'time-to-arrival', and 'time-to-go'. The concept has also proven useful in aircraft conflict resolution and ship piloting, which involve considerably larger time frames. The current study is more specifically concerned with impending collision situations which occur when a driver is approaching a stationary vehicle. The objective was to investigate the determinants of perception-related errors which are thought to contribute to rear-end collisions (Mortimer, 1990). Rear-end collisions represent 20-25% of the total number of accidents, and 80% of rear-end crashes occur in situations where the vehicle struck was stationary or travelling very slowly. A better understanding of the visual information that drivers need to accurately judge TTC in this situation is an important condition for effective preventive action. For the covering abstract, see IRRD 896859.