The Experts below are selected from a list of 6924 Experts worldwide ranked by ideXlab platform
Xiaohua Zhao - One of the best experts on this subject based on the ideXlab platform.
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impact of the connected vehicle environment on tunnel Entrance Zone
Accident Analysis & Prevention, 2021Co-Authors: Guanyang Xing, Xiaohua ZhaoAbstract:Abstract The drastic changes of the space environment at the tunnel Entrance can lead to frequent accidents with higher levels. The connected vehicle environment provides drivers with surrounding traffic information and improve their driving behavior by helping them make safe decisions efficiently. As such, this study is to examine the effects of the connected vehicle environment on driving behavior and safety at the tunnel Entrance Zone. To this end, this research simulates a connected vehicle environment and provides driving aids through the Human-Machine Interface (HMI). Secondly, 40 participants with diverse backgrounds drove the simulator under two different driving conditions: HMI-OFF (traditional driving environment) and HMI-ON (connected vehicle environment). Finally, indicators are selected from speed control, stability and urgency to analyze the impact of the connected vehicle environment on drivers’ behaviors and safety at the warning Zone and tunnel Entrance Zone. The results show that in the connected vehicle environment, the drivers’ speed control in the warning Zone is improved and their deceleration behavior is advanced. The driver's speed control and stability are improved while the danger level of the accident is reduced 100 m ahead of the tunnel Entrance. Besides, the driver's speed control and stability have been both improved 300 m after the tunnel Entrance. Overall, in the connected vehicle environment, the driver can recognize the tunnel in advance and adjust his driving speed in time to ensure his safety at the tunnel Entrance. The results of this study play a critical role in the design and research of warning systems in a connected vehicle environment, and will also guide vehicle manufacturers in designing safety-related functions of automated vehicles. In this research, a connected vehicle environment test platform based on driving simulation technology is constructed and tested in specific tunnel Entrance scenarios, which provides a reference for realizing active protection of vehicles at the tunnel Entrance.
Shy Bassan - One of the best experts on this subject based on the ideXlab platform.
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overview of traffic safety aspects and design in road tunnels
Iatss Research, 2016Co-Authors: Shy BassanAbstract:Abstract This paper reviews aspects of traffic safety and behavior of drivers in road tunnels based on several case studies of traffic accidents along the traffic Zones of tunnel alignment (Entrance: Zone 2; transition Zone: Zone 3; and inner Zone: Zone 4). This paper commences with engineering and design aspects that differentiate between road tunnel and open highways and, afterward, reviews certain issues related to tunnel safety and crashes such as driver behavior, highway alignment, tunnel length, and longitudinal friction. This paper additionally discusses the severity of crashes in road tunnels, specifically severe crashes in road tunnels, including fire incidents and their relationship with vehicle crashes. Finally, additional risk measures and classifications of tunnel safety are introduced. The risk of a crash in a tunnel is reduced compared with crashes on the open road (approximately half); however, tunnel crash severity is higher. The catastrophe potential related to a tunnel fire is higher than in a vehicle crash, even though fire crashes are less frequent than traffic crashes. Drivers in road tunnels generally reduce their speed and increase their lateral position from the right tunnel wall while driving. In shorter tunnels, with reduced driving speed, driver vigilance may be more robust without being hindered by dull driving, which is more common in longer tunnels. Still, in spite of driver alertness, crash rates in tunnels occur due to the tunnel's unusual driving environment. Crash rates are lower in the tunnel inner Zone due to driver alertness, especially after passing the transition Zone and acclimating to the tunnel environment. The number of crashes, however, is higher along Zone 4 (tunnel inner Zone, which is the principal Zone), as it covers longer driving distance. According to most studies, short tunnels were found to exhibit higher crash rates than long tunnels because the Entrance Zones incorporate higher crash rates, compared with the midZones; nonetheless, longer unidirectional (freeway and multilane) tunnels with higher design speed, entail lower driver alertness and diminished concentration due to relatively monotonous driving in spite of a tunnel's closed environment.
Guanyang Xing - One of the best experts on this subject based on the ideXlab platform.
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impact of the connected vehicle environment on tunnel Entrance Zone
Accident Analysis & Prevention, 2021Co-Authors: Guanyang Xing, Xiaohua ZhaoAbstract:Abstract The drastic changes of the space environment at the tunnel Entrance can lead to frequent accidents with higher levels. The connected vehicle environment provides drivers with surrounding traffic information and improve their driving behavior by helping them make safe decisions efficiently. As such, this study is to examine the effects of the connected vehicle environment on driving behavior and safety at the tunnel Entrance Zone. To this end, this research simulates a connected vehicle environment and provides driving aids through the Human-Machine Interface (HMI). Secondly, 40 participants with diverse backgrounds drove the simulator under two different driving conditions: HMI-OFF (traditional driving environment) and HMI-ON (connected vehicle environment). Finally, indicators are selected from speed control, stability and urgency to analyze the impact of the connected vehicle environment on drivers’ behaviors and safety at the warning Zone and tunnel Entrance Zone. The results show that in the connected vehicle environment, the drivers’ speed control in the warning Zone is improved and their deceleration behavior is advanced. The driver's speed control and stability are improved while the danger level of the accident is reduced 100 m ahead of the tunnel Entrance. Besides, the driver's speed control and stability have been both improved 300 m after the tunnel Entrance. Overall, in the connected vehicle environment, the driver can recognize the tunnel in advance and adjust his driving speed in time to ensure his safety at the tunnel Entrance. The results of this study play a critical role in the design and research of warning systems in a connected vehicle environment, and will also guide vehicle manufacturers in designing safety-related functions of automated vehicles. In this research, a connected vehicle environment test platform based on driving simulation technology is constructed and tested in specific tunnel Entrance scenarios, which provides a reference for realizing active protection of vehicles at the tunnel Entrance.
Laura Moretti - One of the best experts on this subject based on the ideXlab platform.
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natural lighting of road pre tunnels a methodology to assess the luminance on the pavement part ii
Tunnelling and Underground Space Technology, 2018Co-Authors: Giuseppe Cantisani, Antonio Dandrea, Laura MorettiAbstract:Abstract This two-part paper presents a comprehensive methodology for lighting calculation of a road pre-tunnel. The adequate lighting of road tunnels, especially in their Entrance Zone during the day-time hours, is a very important factor to maintain road safety and to ensure a good level of service. These targets are commonly achieved by means of artificial lighting systems. In some cases, nevertheless, it could be preferable to build a pre-tunnel, which reduce and control the natural lighting contribution, in the threshold Zone of the tunnel. The structure, in fact, filters the natural light and permits to achieve the required luminance levels on the road pavement, so ensuring the correct visibility to the drivers. The authors expose the theoretical principles and the analysis criteria to control lighting levels in a pre-tunnel lighting (PTL), under various external environmental conditions. The objective of the first part of the paper is to present original analytical models developed by the authors to represent the luminance of clear not terse sky and to assess the illuminance underneath a PTL. The proposed equations permit to compute the sky and PTL contributions considering both direct and reflective radiations, under specific conditions of the examined tunnel (e.g. geometry and materials of PTL, latitude of the site, alignment of the road, etc.). The models and the proposed methodology were also validated by means of an experimental activity, which will be illustrated in the second part of the paper.
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natural lighting of road pre tunnels a methodology to assess the luminance on the pavement part ii
Tunnelling and Underground Space Technology, 2018Co-Authors: Giuseppe Cantisani, Antonio Dandrea, Laura MorettiAbstract:Abstract This two-part paper presents a comprehensive methodology for lighting calculation of a road pre-tunnel. The adequate lighting of road tunnels, especially in their Entrance Zone during the day-time hours, is a very important factor to maintain road safety and to ensure a good level of service. These targets are commonly achieved by means of artificial lighting systems. In some cases, nevertheless, it could be preferable to build a pre-tunnel, which reduces and controls the natural lighting contribution in the threshold Zone of the tunnel. The structure, in fact, filters the natural light and permits to achieve the required luminance levels on the road pavement, so ensuring the correct visibility to the drivers. Analytical models were developed in the first part of the paper to describe the sky illumination of a clear but not terse sky, which is typical in large cities and industrial areas, and to evaluate the consequences related to the construction of a pre-tunnel lighting (PTL). This second part presents the validation procedures adopted to verify the proposed models. Particularly, a luxmeter photo-radiometer has been used for validating the clear not terse sky model and several PTL scale models were used to validate the methodology proposed to assess the pavement luminance. The geometry of the PTL, its alignment and materials have been varied to obtain several results under various meteorological and climatic conditions. The results obtained from the experimental research program showed that the proposed models, inherent both the sky luminance and the illuminance on the road, ensure a good approximation respect to the real measures performed. In particular, for the sky luminance, the proposed theoretical distribution implies an average deviation respect to the experimental data equal to 5%. The calculated illuminance under the PTL differs on average from the measured values for −1.26%.
Zhao R - One of the best experts on this subject based on the ideXlab platform.
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Evaluation of effectiveness of speed reduction markings on driving speed in highway tunnel Entrance and exit areas
'Faculty of Transport and Traffic Sciences', 2020Co-Authors: Zhu T, Wang C, Yang C, Zhao RAbstract:© 2020, Faculty of Transport and Traffic Engineering. All rights reserved. Tunnels are critical areas for highway safety because the severity of crashes in tunnels tends to be more serious. Controlling vehicle speed is regarded as a feasible measure to reduce the accident rate in the tunnel Entrance and exit areas. This paper aims to evaluate the effectiveness of three types of speed reduction markings (SRMs) in tunnel Entrance and exit Zones by conducting a driving simulation experiment. For this study, 25 drivers completed the driving tasks in the day and night scenarios. The vehicle speed and acceleration data were collected for analysing and the relative speed contrast, time mean speed and acceleration were adopted as indices to evaluate the effectiveness of SRMs. The repeated ANOVA test results revealed that SRMs have a significant effect in reducing vehicle speed, especially in the exit Zone. Colour Anti-skid Markings (CASMs) produced a more obvious deceleration in the Entrance Zone. In the Entrance Zone, a similar downward trend was performed in the situation of NSRMs and SRMs, but a lower speed occurred in case of SRMs. Besides, CASMs work better and cause an obvious gap of 10 km/h in daytime and 5 km/h at night compared to the speed without SRMs. In the exit Zone, the present study supports the conclusion that the drivers are prone to accelerate. Our results showed that the drivers accelerated in case of NSRMs, while they slowed down in case of SRMs. Thus, SRMs are necessarily implemented in the highway tunnel Entrance and exit Zones. Our study also indicates that though CASMs result in lower speed at night, the Transverse Speed Reduction Markings (TSRMs) have a better performance than CASMs in daytime. The investigation provides essential information for developing a new marking design criterion and intelligent driver support systems in the highway tunnel Zones