4,446 research outputs found

    Evaluation of a sudden brake warning system: Effect on the response time of the following driver

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    This study used a video-based braking simulation dual task to carry out a preliminary evaluation of the effect of a sudden brake warning system (SBWS) in a leading passenger vehicle on the response time of the following driver. The primary task required the participants (N = 25, 16 females, full NZ license holders) to respond to sudden braking manoeuvres of a lead vehicle during day and night driving, wet and dry conditions and in rural and urban traffic, while concurrently performing a secondary tracking task using a computer mouse. The SBWS in the lead vehicle consisted of g-force controlled activation of the rear hazard lights (the rear indicators flashed), in addition to the standard brake lights. Overall, the results revealed that responses to the braking manoeuvres of the leading vehicles when the hazard lights were activated by the warning system were 0.34 s (19%) faster compared to the standard brake lights. The SBWS was particularly effective when the simulated braking scenario of the leading vehicle did not require an immediate and abrupt braking response. Given this, the SBWS may also be beneficial for allowing smoother deceleration, thus reducing fuel consumption. These preliminary findings justify a larger, more ecologically valid laboratory evaluation which may lead to a naturalistic study in order to test this new technology in ‘real world’ braking situations

    Depth perception of coloured lights in motion under difficult seeing conditions.

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    On the relationships between self-reported bicycling injuries and perceived risk among cyclists in Queensland, Australia

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    The focus of governments on increasing active travel has motivated renewed interest in cycling safety. Bicyclists are up to 20 times more likely to be involved in serious injury crashes than drivers so understanding the relationship among factors in bicyclist crash risk is critically important for identifying effective policy tools, for informing bicycle infrastructure investments, and for identifying high risk bicycling contexts. This study aims to better understand the complex relationships between bicyclist self reported injuries resulting from crashes (e.g. hitting a car) and non-crashes (e.g. spraining an ankle) and perceived risk of cycling as a function of cyclist exposure, rider conspicuity, riding environment, rider risk aversion, and rider ability. Self reported data from 2,500 Queensland cyclists are used to estimate a series of seemingly unrelated regressions to examine the relationships among factors. The major findings suggest that perceived risk does not appear to influence injury rates, nor do injury rates influence perceived risks of cycling. Riders who perceive cycling as risky tend not to be commuters, do not engage in group riding, tend to always wear mandatory helmets and front lights, and lower their perception of risk by increasing days per week of riding and by increasing riding proportion on bicycle paths. Riders who always wear helmets have lower crash injury risk. Increasing the number of days per week riding tends to decrease both crash injury and non crash injury risk (e.g. a sprain). Further work is needed to replicate some of the findings in this study

    The Influence of Fog on Motion Discrimination Thresholds in Car Following

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    A possible explanation for close following in fog is that it would allow drivers to control headway more precisely by reducing motion perception thresholds. The purpose of our experiments was to determine the motion discrimination thresholds for closing and receding under normal and foggy conditions. An experiment and a pilot study were conducted on a driving simulator in which subjects were presented with a car following situation. Subjects had to press a button as soon as they detected that the lead vehicle was closing or receding, and their choice response time was recorded. Several visibility conditions were tested corresponding to different contrasts between the lead vehicle outline and the background, ranging from clear weather conditions to foggy conditions in which the vehicle could only be seen by its rear lights. Initial headway and lead vehicle acceleration were also varied. As expected, response times were longest with small accelerations and long headways. There was also an effect of visibility conditions with longer response times when the contrast between the vehicle outline and the background was 5% or less. Moreover, the reduction of response time corresponding to a reduction of headway was greater in fog than in clear conditions, at least in the given range of distances. This suggests that driving closer in fog may have a perceptual-control benefit in terms of a reduction in response times that partially offsets the reduction in timeheadway. Driving closer may also benefit lateral trajectory control because the lead vehicle is less likely to be lost in fog

    A Neural network approach to visibility range estimation under foggy weather conditions

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    Š 2017 The Authors. Published by Elsevier B.V. The degradation of visibility due to foggy weather conditions is a common trigger for road accidents and, as a result, there has been a growing interest to develop intelligent fog detection and visibility range estimation systems. In this contribution, we provide a brief overview of the state-of-the-art contributions in relation to estimating visibility distance under foggy weather conditions. We then present a neural network approach for estimating visibility distances using a camera that can be fixed to a roadside unit (RSU) or mounted onboard a moving vehicle. We evaluate the proposed solution using a diverse set of images under various fog density scenarios. Our approach shows very promising results that outperform the classical method of estimating the maximum distance at which a selected target can be seen. The originality of the approach stems from the usage of a single camera and a neural network learning phase based on a hybrid global feature descriptor. The proposed method can be applied to support next-generation cooperative hazard & incident warning systems based on I2V, I2I and V2V communications. Peer-review under responsibility of the Conference Program Chairs

    A Study on Recent Developments and Issues with Obstacle Detection Systems for Automated Vehicles

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    This paper reviews current developments and discusses some critical issues with obstacle detection systems for automated vehicles. The concept of autonomous driving is the driver towards future mobility. Obstacle detection systems play a crucial role in implementing and deploying autonomous driving on our roads and city streets. The current review looks at technology and existing systems for obstacle detection. Specifically, we look at the performance of LIDAR, RADAR, vision cameras, ultrasonic sensors, and IR and review their capabilities and behaviour in a number of different situations: during daytime, at night, in extreme weather conditions, in urban areas, in the presence of smooths surfaces, in situations where emergency service vehicles need to be detected and recognised, and in situations where potholes need to be observed and measured. It is suggested that combining different technologies for obstacle detection gives a more accurate representation of the driving environment. In particular, when looking at technological solutions for obstacle detection in extreme weather conditions (rain, snow, fog), and in some specific situations in urban areas (shadows, reflections, potholes, insufficient illumination), although already quite advanced, the current developments appear to be not sophisticated enough to guarantee 100% precision and accuracy, hence further valiant effort is needed

    A Survey of Driving Research Simulators Around the World.

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    The literature review is part of the EPSRC funded project "Driver performance in the EPSRC driving simulator: a validation study". The aim of the project is to validate this simulator, located at the Department of Psychology, University of Leeds, and thereby to indicate the strengths and weaknesses of the existing configuration. It will provide guidance on how the simulator can be modified and overcome any deficiencies that are detected and also provide "benchmarks" against which other simulators can be compared. The literature review will describe the technical characteristics of the most well-known driving simulators around the world, their special features and their application areas until today. The simulators will be described and compared according to their cost (low, medium and high) and also contact addresses and photographs of the simulators will be provided by the end of the paper. In the process of gathering this information, it became apparent that there are mainly two types of papers published - either in journals or in proceedings from conferences: those describing only the technical characteristics of a specific simulator and those referring only to the applications of a specific simulator. For the first type of papers, the level of detail, format and content varies significantly where for the second one it has been proven extremely difficult to find any information about the technical characteristics of the simulator where the study had been carried out. A number of details provided in this paper are part of personal communication, or personal visits to those particular driving simulator centres or from the World Wide Web. It should also be noted here that most of the researchers contacted here offered very detail technical characteristics and application areas of their driving simulators and the author is grateful to them

    Quality and field of vision - a review of the needs of drivers and riders: phase 1 report.

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    It is the responsibility of the Department of the Environment, Transport and the Regions (DETR) to promote safe use of the UK road network. Driver vision has been identified as major determinant to this and factors which impede it require further investigation. This project is specifically concerned with the effect on driver / rider vision of: • windscreen and visor tinting, installed light transmission, haze, abrasion, damage and repair, • the use and positioning of wider structural member (particularly A-pillars) to improve crashworthiness, aerodynamics and rigidity. The first phase of the work is to understand the current status regarding the above factors and the rationale for it. A variety of sources have been consulted for this information including: • establishing contact with interested parties, • reviewing and establishing the basis of EC Directives and other regulations, • reviewing and summarising previous, current and proposed research, • analysing available accident data, • interviewing drivers and riders. A detailed work plan for the remainder of the project has been developed based on the results of the Phase 1 findings and on the professional experience ICE Ergonomics has in this field

    Effects of Visibility and Alarm Modality on Workload, Trust in Automation, Situation Awareness, and Driver Performance

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    Driving demands sustained driver attention. This attentional demand increases with decreasing field visibility. In the past researchers have explored and investigated how collision avoidance warning systems (CAWS) help improve driving performance. The goal of the present study is to determine whether auditory or tactile CAWS have a greater effect on driver performance, perceived workload, system trust, and situation awareness (SA). Sixty-three undergraduate students from Old Dominion University participated in this study. Participants were asked to complete two simulated driving sessions along with Motion Sickness Susceptibility Questionnaire, Background Information Questionnaire, Trust Questionnaire, NASA Task Load Index Questionnaire, Situation Awareness Rating Technique Questionnaire, and Simulator Sickness Questionnaire. Analyses indicated that drivers in the tactile modality condition had low perceived workload. Drivers in the heavy fog visibility condition had the highest number of collisions and red-light tickets. Drivers in the heavy fog condition also reported having the highest overall situation awareness. Drivers in the clear visibility condition trusted tactile alarms more than the auditory alarms, whereas drivers in the heavy fog condition trusted auditory alarms more than tactile alarms. The findings of this investigation could be applied to improve the design of CAWS that would help improve driver performance and increase safety on the roadways
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