The Experts below are selected from a list of 129 Experts worldwide ranked by ideXlab platform
S E Jenkins - One of the best experts on this subject based on the ideXlab platform.
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the performance of modern Retroreflective Material in the road traffic environment i visual acquisition and sign legibility
Transportation Research Board Annual Meeting 83rd 2004 Washington DC USA, 2004Co-Authors: S E JenkinsAbstract:The use of Retroreflective sheeting has been primarily driven by the photometric performance of the sheeting with little regard to assessing the effectiveness of various sheeting types in meeting drivers' signing needs under different road traffic scenarios. The advent of microprismatic sheeting allows for much greater freedom in the design of the photometric performance of the sheeting. The questions of where and whether to use microprismatic sheeting has generated increased confusion in the State Road Authorities and Local Governments and has become a major issue within Standards setting bodies. The objective of this paper is to provide some guidance as to the performance of signs made from the different types of sheeting and how each should best be used to benefit the driver. Two partial models of visual acquisition of sign information are proposed that are relevant to the Retroreflective performance of traffic signs. They are a visual scanning-type model and a visual conspicuity-type model. The major consequence of the two models for Retroreflective sheeting is that they operate over different distance ranges. A model of the sign luminance as a function of distance from the sign is proposed based on a review of previous legibility studies. The model suggests two criteria, one for an adequate sign luminance that will meet driver requirements for most situations and one for optimal sign luminance that will cater for high luminance complex surrounds, older drivers and sign conspicuity.
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the performance of modern Retroreflective Material in the road traffic environment ii legibility of two classes of sign sheeting
Transportation Research Board Annual Meeting 83rd 2004 Washington DC USA, 2004Co-Authors: S E JenkinsAbstract:The luminance of signs of two different Retroreflective Materials in various road situations is compared to the two performance categories dictated by driver legibility capabilities. By the use of a computer modeling program, the luminance of a sign was calculated as a function of approach distance (the supply model) for a set of parameters including sheeting type, vehicle type, headlight beam pattern, road geometry, sign position and lane position. The drivers' nighttime requirements (the demand model) were taken from the previous paper. When the demand curves are overlaid onto the supply curves, it is then apparent whether the different sheeting types can meet the requirements of the drive. From the two sheeting types that were compared, ASTM Type III (high Intensity encapsulated glass-bead Material) and Type IX (very high intensity unmetalized microprismatic with high retroreflectivity at short road distances) the broad conclusions drawn are that: Type IX microprismatic sheeting has luminances that are several times that of beaded Type III sheeting over all distances and all road geometries Type IX sheeting has superior performance for vehicles that impose a large observation angle on drivers, such as trucks, buses, vans and trams. HI does not meet the minimum requirements of drivers of these types of vehicle. Consequently, it should be the sheeting of choice where there is diversity in the vehicle mix. The increased luminance provided by the Type IX sheeting over that of the beaded Type III sheeting would particularly benefit the older drivers in the legibility task.
Lei Wang - One of the best experts on this subject based on the ideXlab platform.
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The Study of Retroreflective Material Based on Mesopic Vision Theory
2016Co-Authors: Chuan Zheng Zhu, Yong Yang, Lei WangAbstract:spectrum Abstract. The coefficient of retroreflection is considered as the most important parameter of Retroreflective Material, the value of which is tested by photopic detector now. In fact this Material were usually used under mesopic vision condition, and through the test of Retroreflective spectra, the mesopic spectral luminous efficiency Vmes(λ) and equivalent brightness were calculated. The result show that at different brightness the Retroreflective light present unlike spectrum distribution, and white, blue Material with higher retroreflection value under mesopic vision, red Material own lower value, this phenomenon is more apparent with the decrease of brightness
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the study of Retroreflective Material based on mesopic vision theory
Applied Mechanics and Materials, 2012Co-Authors: Chuan Zheng Zhu, Yong Yang, Lei WangAbstract:The coefficient of retroreflection is considered as the most important parameter of Retroreflective Material, the value of which is tested by photopic detector now. In fact this Material were usually used under mesopic vision condition, and through the test of Retroreflective spectra, the mesopic spectral luminous efficiency Vmes(λ) and equivalent brightness were calculated. The result show that at different brightness the Retroreflective light present unlike spectrum distribution, and white, blue Material with higher retroreflection value under mesopic vision, red Material own lower value, this phenomenon is more apparent with the decrease of brightness.
Chuan Zheng Zhu - One of the best experts on this subject based on the ideXlab platform.
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The Study of Retroreflective Material Based on Mesopic Vision Theory
2016Co-Authors: Chuan Zheng Zhu, Yong Yang, Lei WangAbstract:spectrum Abstract. The coefficient of retroreflection is considered as the most important parameter of Retroreflective Material, the value of which is tested by photopic detector now. In fact this Material were usually used under mesopic vision condition, and through the test of Retroreflective spectra, the mesopic spectral luminous efficiency Vmes(λ) and equivalent brightness were calculated. The result show that at different brightness the Retroreflective light present unlike spectrum distribution, and white, blue Material with higher retroreflection value under mesopic vision, red Material own lower value, this phenomenon is more apparent with the decrease of brightness
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the study of Retroreflective Material based on mesopic vision theory
Applied Mechanics and Materials, 2012Co-Authors: Chuan Zheng Zhu, Yong Yang, Lei WangAbstract:The coefficient of retroreflection is considered as the most important parameter of Retroreflective Material, the value of which is tested by photopic detector now. In fact this Material were usually used under mesopic vision condition, and through the test of Retroreflective spectra, the mesopic spectral luminous efficiency Vmes(λ) and equivalent brightness were calculated. The result show that at different brightness the Retroreflective light present unlike spectrum distribution, and white, blue Material with higher retroreflection value under mesopic vision, red Material own lower value, this phenomenon is more apparent with the decrease of brightness.
Yong Yang - One of the best experts on this subject based on the ideXlab platform.
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The Study of Retroreflective Material Based on Mesopic Vision Theory
2016Co-Authors: Chuan Zheng Zhu, Yong Yang, Lei WangAbstract:spectrum Abstract. The coefficient of retroreflection is considered as the most important parameter of Retroreflective Material, the value of which is tested by photopic detector now. In fact this Material were usually used under mesopic vision condition, and through the test of Retroreflective spectra, the mesopic spectral luminous efficiency Vmes(λ) and equivalent brightness were calculated. The result show that at different brightness the Retroreflective light present unlike spectrum distribution, and white, blue Material with higher retroreflection value under mesopic vision, red Material own lower value, this phenomenon is more apparent with the decrease of brightness
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the study of Retroreflective Material based on mesopic vision theory
Applied Mechanics and Materials, 2012Co-Authors: Chuan Zheng Zhu, Yong Yang, Lei WangAbstract:The coefficient of retroreflection is considered as the most important parameter of Retroreflective Material, the value of which is tested by photopic detector now. In fact this Material were usually used under mesopic vision condition, and through the test of Retroreflective spectra, the mesopic spectral luminous efficiency Vmes(λ) and equivalent brightness were calculated. The result show that at different brightness the Retroreflective light present unlike spectrum distribution, and white, blue Material with higher retroreflection value under mesopic vision, red Material own lower value, this phenomenon is more apparent with the decrease of brightness.
Dragana Macura - One of the best experts on this subject based on the ideXlab platform.
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Model for Predicting Traffic Signs Functional Service Life – The Republic of Croatia Case Study
Promet-traffic & Transportation, 2017Co-Authors: Dario Babić, Darko Babić, Dragana MacuraAbstract:Traffic signs are the basic elements of communication between the relevant road authorities and road users. They manage, regulate, inform and warn road users to ensure their safe movement throughout transport networks. Traffic signs must be timely visible to all traffic participants in all weather and traffic conditions in order to fulfil their function, which means they must have satisfactory retroreflection properties. This paper presents a research of the deterioration of traffic signs retroreflection. The aim of this article is to develop models that will effectively enable predicting the retroreflection of traffic signs and thus optimize the maintenance activities and replacement of road signs to increase road safety. The research included measurements of retroreflection of Retroreflective Material Classes I and II (white, red and blue colour) and Class III (red and yellow colour). Based on the collected data from the City of Zagreb (Republic of Croatia), the authors developed the models to estimate the functional service life of certain colours and Materials used to make traffic signs. Considering that the average coefficient of determination for all the models is between 0.55-0.60, they present an effective tool in the traffic sign maintenance system.
