An analysis of 'looked but failed to see' accidents involving parked police vehicles

Drivers who collide with a vehicle that is parked on the hard shoulder of a motorway or dual-carriageway sometimes claim not to have seen it before the collision. Previous research into vehicle conspicuity has taken such ‘looked but failed to see’ claims at face value, and concentrated on attempting to remedy the problem by making vehicles more conspicuous in sensory terms. However, the present study describes investigations into accidents of this kind which have involved stationary police cars, vehicles which are objectively highly conspicuous. Two laboratory studies showed that experienced drivers viewing a film of dual-carriageway driving were slower to respond to a parked police car as a ‘hazard’ if it was parked directly in the direction of travel than if it was parked at an angle; this effect was more pronounced when the driver's attention was distracted with a secondary reasoning task. Taken together with the accident reports, these results suggest that ‘looked but failed to see’ accidents may arise not because the parked vehicle is difficult to see, but for more cognitive reasons, such as vigilance failure, or possession by the driver of a ‘false hypothesis’ about the road conditions ahead. An emergency vehicle parked in the direction of travel, with only its blue lights flashing, may encourage drivers to believe that the vehicle is moving rather than stationary. Parking at an angle in the road, and avoiding the use of blue lights alone while parked, are two steps that drivers of parked emergency vehicles should consider taking in order to alert approaching drivers to the fact that a stationary vehicle is ahead.     

Determining optimum flash patterns for emergency service vehicles: An experimental investigation using high definition film

An investigation of how emergency vehicle lighting (EVL) can be improved is reported with reference to an analysis of police vehicle road traffic accidents (Study 1). In Study 2, 37 regular drivers were shown film clips of a marked police vehicle, in which flash rate (1 Hz, 4 Hz) and pattern (single, triple pulse) were varied on the blue Light Emitting Diode (LED) roofbar. Results indicate a 4 Hz flash rate conveys greater urgency than a 1 Hz rate, while a 1 Hz, single flash combination was ranked the least urgent of all combinations. Participants claimed they would leave significantly more space before pulling out in front of an approaching police car (gap acceptance) in the 4 Hz single pulse condition in comparison to other EVL combinations. The preliminary implications for which flash characteristics could prove most optimal for emergency service use are discussed with regard to effects on driver perception and expected driving behaviour.     

基于层次颜色Petri网的交通紧急调度算法与建模

针对城市交通网络中紧急车辆在行驶区段中如何较快地到达终点的问题,提出了一种基于Petri网的交通紧急控制策略模型。利用Davidson函数中行驶时间与交通流之间的对应关系,得出紧急车辆在道路上的最短行驶时间,并将其作为权重,运用Dijkstrsa算法进行最短路径寻优;采用紧急信号灯控制策略对最短路径上的交叉口信号灯进行了调整,减少紧急车辆在交叉口的延滞时间,并运用Petri网理论,建立紧急车辆在交叉口的紧急信号灯控制模型。为了描述紧急信号灯控制策略的动态行为特性,将其各部分关键要素分别设计为相应的Petri网子模型。通过模型的一个仿真实例,进行了紧急控制策略与普通策略的实验对比,实验结果表明前者可以对紧急车辆的到达时间进行优化。     

An Intelligent Transportation System Application for Smartphones Based on Vehicle Position Advertising and Route Sharing in Vehicular Ad-Hoc Networks

关于到来的紧急情况车辆和他们的线路警告司机能极大地在拥挤的城市里改进他们的旅行时间,当由于分心减少事故的风险时。这份报纸由建议耶稣,能够关于象救护车一样的到来的紧急情况车辆通知常规车辆的机器人应用,警察汽车和消防队贡献这个目标。这被创造能够直接在他们之间交流的车辆的一个网络使可能。因此,用户能由考虑到来的警戒以一种及时方式作开车决定。用我们的 GRCBox 硬件的支持,申请能在 5 GHz 乐队依靠车辆的特定的网络通讯, V2V (vehicle-to-vehicle ) 通讯通过基于机器人的 smartphone 和我们的 GRCBox 设备的联合正在被提供。申请与阻塞的不同层次在三种不同情形被测试,证明提供有能力第二在不到一个以内提醒起来注意 300 米,和通知车辆。     

Slipping,tripping and falling accidents to delivery drivers

North American studies have shown that approximately 25% of injuries to drivers of commercial vehicles are caused by slipping, tripping and falling accidents and a large proportion of these are associated with entry to and exit from the vehicle.

No similar data have been obtained for delivery drivers within the U.K. and a study has therefore been carried out to investigate the slipping, tripping and falling accidents sustained during the distribution of products using commercial road vehicles. Accident information from two companies which operate large commercial vehicle fleets has been analysed and data on slipping, tripping and falling accidents to drivers have been examined using a sequential accident model in order to identify contributory factors. Entry and exit systems to and from the vehicles have been evaluated and compared with the minimum requirements which have been proposed by various authorities. A questionnaire survey of drivers has also been carried out to determine the comments of the user population in order to identify additional factors which may contribute to the level of hazard. The need for further research to provide comprehensive guidelines for vehicle system designers has been identified.     

An ergonomics approach to the problem of high vehicles striking low bridges

The incidence of high vehicles striking low bridges has increased considerably since about 1970. Now, between 400-500 such accidents occur every year. This study investigated two possible reasons for the accidents. These were drivers' knowledge of their vehicle heights, and drivers' understanding of the low bridge warning signs. Drivers' opinions of ways of preventing the accidents were also obtained. Only 12% of drivers were correct in their estimate of their vehicle height and 27% were within 3 in (76 mm) of the correct height. The majority of drivers made estimates which erred on the 'safe' side. 21% of drivers did not understand the road sign that shows 'Headroom at hazard ahead'. The ways of preventing high vehicles striking low bridges most popular with the drivers were those which provided them with information which was most directly relevant, ie, whether or not the vehicle would get safely under the bridge.     

Visual attention while driving: sequences of eye fixations made by experienced and novice drivers

Eye fixations were recorded while novice and experienced drivers drove along three types of roads (rural, suburban and dual-carriageway). An analysis of the content of those fixations was performed in order to identify differences in the scanpaths that can be associated with skill acquisition and that can indicate a sensitivity to road type. This analysis itemized the part of the visual scene that was inspected with each fixation, and identified what the driver looked at as a function of what they had looked at previously. Single-fixation, two-fixation, and three-fixation patterns of eye-movements were identified. Differences in sequences of fixations were found between novice and experienced drivers on the three types of roads, with experienced drivers showing greater sensitivity overall, and with some stereotypical transitions in the visual attention of the novices. A number of individual sequences were identified, including a roadway preview pattern (alternating fixations between near and far views of the road ahead), and patterns involving mirror inspections that varied according to the road type.     

Visual attention while driving: sequences of eye fixations made by experienced and novice drivers

Eye fixations were recorded while novice and experienced drivers drove along three types of roads (rural, suburban and dual-carriageway). An analysis of the content of those fixations was performed in order to identify differences in the scanpaths that can be associated with skill acquisition and that can indicate a sensitivity to road type. This analysis itemized the part of the visual scene that was inspected with each fixation, and identified what the driver looked at as a function of what they had looked at previously. Single-fixation, two-fixation, and three-fixation patterns of eye-movements were identified. Differences in sequences of fixations were found between novice and experienced drivers on the three types of roads, with experienced drivers showing greater sensitivity overall, and with some stereotypical transitions in the visual attention of the novices. A number of individual sequences were identified, including a roadway preview pattern (alternating fixations between near and far views of the road ahead), and patterns involving mirror inspections that varied according to the road type.     

Automatic LightBeam Controller for driver assistance

In this article, we present an effective system for detecting vehicles in front of a camera-assisted vehicle (preceding vehicles traveling in the same direction and oncoming vehicles traveling in the opposite direction) during night-time driving conditions in order to automatically change vehicle head lights between low beams and high beams avoiding glares for the drivers. Accordingly, high beams output will be selected when no other traffic is present and will turn low beams on when other vehicles are detected. In addition, low beams output will be selected when the vehicle is in a well lit or urban area. LightBeam Controller is used to assist drivers in controlling vehicle’s beams increasing its correct use, since normally drivers do not switch between high beams and low beams or vice versa when needed. Our system uses a B&W forward looking micro-camera mounted in the windshield area of a C4-Picasso prototype car. Image processing techniques are applied to analyse light sources and to detect vehicles in the images. Furthermore, the system is able to classify between vehicle lights and road signs reflections or nuisance artifacts by means of support vector machines. The algorithm is efficient and able to run in real time. The system has been tested with different video sequences (more than 7 h of video sequences) under real night driving conditions in different roads of Spain. Experimental results, a comparison with other representative state of the art methods and conclusions about the system performance are presented.     

嵌入式处理系统在智能高清卡口中的应用

针对目前交通管理的现状,阐述了对于智能高清卡口中采用嵌入式处理系统的卡口终端服务器的需求和所应研究的内容,给出了系统的拓扑结构,介绍了系统设计方案,描述了终端服务器软件的主要功能。该系统能为车辆超速处罚、车辆布控、车辆及驾驶人关联排查等公安业务提供高质量的数据源,有效遏制车辆超速等违章行为,控制并减少道路交通事故。     

Multi-Level Planning for Semi-autonomous Vehicles in Traffic Scenarios Based on Separation Maximization

The planning of semi-autonomous vehicles in traffic scenarios is a relatively new problem that contributes towards the goal of making road travel by vehicles free of human drivers. An algorithm needs to ensure optimal real time planning of multiple vehicles (moving in either direction along a road), in the presence of a complex obstacle network. Unlike other approaches, here we assume that speed lanes are not present and that different lanes do not need to be maintained for inbound and outbound traffic. Our basic hypothesis is to carry forward the planning task to ensure that a sufficient distance is maintained by each vehicle from all other vehicles, obstacles and road boundaries. We present here a 4-layer planning algorithm that consists of road selection (for selecting the individual roads of traversal to reach the goal), pathway selection (a strategy to avoid and/or overtake obstacles, road diversions and other blockages), pathway distribution (to select the position of a vehicle at every instance of time in a pathway), and trajectory generation (for generating a curve, smooth enough, to allow for the maximum possible speed). Cooperation between vehicles is handled separately at the different levels, the aim being to maximize the separation between vehicles. Simulated results exhibit behaviours of smooth, efficient and safe driving of vehicles in multiple scenarios; along with typical vehicle behaviours including following and overtaking.     

基于Ad-Hoc无线网络的自主式道路通行状况信息系统

提出了一个基于Ad-Hoc无线网络的交通信息系统的概念.该系统中,车辆收集特定的信息,并按照协议与周边车辆进行信息交换,并且利用车辆本身的运动来完成信息的传播.在获取足够的信息后,车辆能够计算出前方道路的平均交通状况,并显示给驾驶员作为行车参考.     

Machine learning in road accident research: decision trees describing road accidents during cross-flow turns

In-depth studies of behavioural factors in road accidents using conventional methods are often inconclusive and costly. In a series of studies exploring alternative approaches, 200 cross-flow junction road accidents were sampled from the files of Nottinghamshire Constabulary, UK, coded for computer analysis using a specially devised ‘Traffic Related Action Analysis Language’, and then examined using different computational and statistical techniques. The present study employed an AI machine-learning method based on Quinlan's ‘ID3’ algorithm to create decision trees distinguishing the characteristics of accidents that resulted in injury or in damage only; accidents of young male drivers; and those of the relatively more and less dangerous situations. For example the severity of accidents involving turning onto a main road could be determined with 79% accuracy from the nature of the other vehicle, season, junction type, and whether the Turner failed to notice another road user. Accidents involving young male drivers could be identified with 77% accuracy by knowing if the junction was complex, and whether the Turner waited or slowed before turning.     

The effect of communicational signals on drivers' subjective appraisal and visual attention during interactive driving scenarios

Communicational signals (e.g. lights and horns) are imperative for on-road interaction between drivers. The aim of the present study was to explore how these signals affect drivers' subjective appraisal and visual attention, and how drivers decode the signals from other vehicles within a variety of interactive contexts. Twenty-five male participants (20 valid samples, ranging from 21 to 29 years of age) were recruited to watch film clips of pre-designed interactive scenarios involving common vehicle signals in a full-view simulator (i.e. including road view and mirror views). Participants' attitudes towards the interacting vehicle's behaviours, emotional responses, fixation metrics, and decoded meanings were recorded and analysed. The majority of tested signals, with the exception of the horn used in the behind vehicles, significantly improved drivers' attitudes and pleasure. All signals significantly increased emotional arousal, as well as the total fixation time and mean fixation duration on the interacting vehicle. When the interacting vehicle was visible in mirrors, the signal usage significantly increased the fixation frequency towards it. Meanwhile, a significant decrease in total fixation time and mean fixation duration on the road was reported. The results also demonstrated that the decoded signal contained several meanings simultaneously depending on both the signal type and its interactive context. This study quantified the communication process via vehicular signals under typical situations involving other vehicles, and also suggested new ideas on how to establish more advanced communication between drivers.     

Visual attention and the transition from novice to advanced driver

Inexperienced drivers are particularly vulnerable to road traffic accidents, and inattention emerges as a factor in these accidents. What do these drivers attend to and how can their observation skills be developed? When drivers scan the road around them, differences are observed as function of driving experience and training, with experienced drivers increasing their visual scanning on roadways of increasing complexity. Trained police drivers showed this effect of increased scanning even more than experienced drivers. This suggests that the driver's understanding of the task develops with experience, such that roads that demand increased monitoring (e.g. interweaving traffic on a multi-lane highway) receive more extensive scanning than roads that are simpler (e.g. light traffic on a straight rural road). Novice drivers do not show this sensitivity to road complexity, suggesting that they fail to attend to potential dangers involving the behaviour of other road users. Encouragingly, a simple training intervention can increase the visual scanning of novices.     

Processes and countermeasures in overtaking road accidents

Of police road accident files describing overtaking accidents, 973 were sampled from the headquarters of Nottinghamshire Constabulary, UK for 1989–1993. Of particularly detailed cases, 410 were examined in depth and salient facts extracted including the exact manoeuvre involved, the errors made by drivers, the reasons for error, and the principal behavioural countermeasures that would have prevented the accident. Particular hazards were: (1) oncoming vehicles that only came into view during the overtake, from turnings, bends and hill crests, and (2) collisions involving the same direction cohort. The most effective single countermeasure was to avoid overtaking a vehicle travelling at or near the speed limit. The study illustrates the 'structured judgement method' of accident causation research in which human interpreters are used to assign causes and processes to individual cases, but orthodox research techniques are used to standardize procedures, and to assess and ensure reliability.     

Human factors and road safety. Overview of research at the University of Michigan Transportation Research Institute between 1977 and 1986

This article presents a brief overview of the research performed at tge Human Factors Division of The University of Michigan Transportation Research Institute between 1977 and 1986. The focus of the research has been on human factors (ergonomics) aspects of road safety. Specifically, the research has dealt with the following issues: vehicle headlighting, vehicle rear lighting and signalling, vehicle displays and controls, vehicle components, conspicuity of vehicles, legibility of traffic signs and licence plates, driver reaction time, driver performance, stopping sight distance, driver seated position, individual differences (drivers with disabilities, older drivers), methods for measuring blood alcohol concentration, societal violence and traffic accidents, cross-cultural comparison of driver risk-perception, and theoretical issues.     

Speed choice by drivers: the issue of driving too slowly

Quite correctly, the majority of road safety speeding initiatives focus on drivers travelling at excessive speeds. This study, however, focused on the potential problem of driving too slowly. Six thousand, four hundred and eighty vehicles from around the Perth metropolitan area in Western Australia had their speeds recorded; observations were also made of these vehicles to identify characteristics of the driver and vehicle. In addition, a community survey with 240 members of the public was conducted to examine their attitudes towards slow drivers. As expected, results showed that older drivers drove more slowly than the other age brackets, women drove more slowly than men, and that heavily laden vehicles drove more slowly than other types of vehicles. Additionally, the slowest days were weekdays and the quickest were Saturdays. Community attitudes, generally mirrored the observational findings, and indicated that the public believed that slow driving was sometimes a safety problem causing some accidents. These data are discussed, and some possible countermeasures are briefly introduced to address the problem.     

Speed choice by drivers: The issue of driving too slowly

Quite correctly, the majority of road safety speeding initiatives focus on drivers travelling at excessive speeds. This study, however, focused on the potential problem of driving too slowly. Six thousand, four hundred and eighty vehicles from around the Perth metropolitan area in Western Australia had their speeds recorded; observations were also made of these vehicles to identify characteristics of the driver and vehicle. In addition, a community survey with 240 members of the public was conducted to examine their attitudes towards slow drivers. As expected, results showed that older drivers drove more slowly than the other age brackets, women drove more slowly than men, and that heavily laden vehicles drove more slowly than other types of vehicles. Additionally, the slowest days were weekdays and the quickest were Saturdays. Community attitudes, generally mirrored the observational findings, and indicated that the public believed that slow driving was sometimes a safety problem causing some accidents. These data are discussed, and some possible countermeasures are briefly introduced to address the problem.     

DRIVERS' GALVANIC SKIN RESPONSE AND THE RISK OF ACCIDENT

Galvanic skin responses of 20 drivers were measured in two studies covering a wide range of roads and road conditions. Accident histories wore obtained for the roads in one of the studies. It is shown that the level of GSR activity does not depend primarily on the nature of the road or conditions. Consistent sources of variation in the GSR are observed, one of them apparently being the subject's experience of driving. The distribution of GSR per unit distance travelled was found to be similar to the distribution of accidents per unit total distance of vehicle travel (the accident rate). The results support a view that driving is a self-paced task governed' by the level of emotional tension or anxiety which the driver wishes to tolerate. The possible effects of this on the distribution of accidents is discussed.