不同隧道侧壁涂料对汽车司机视觉反应的研究

驾驶员前方视野直接影响其对危险状况的预判和处理,侧壁属于驾驶员驾车经过公路隧道时前方视野感知域的重要组成部分,因此对行车安全具有一定的影响。文章首先采用分光辐射式亮度计对不同侧壁材料的照明参数进行测定。然后结合自主研发的公路隧道照明环境模拟和效果评价装置开展试验。通过室内模拟具有相同亮度指标的公路隧道照明环境,以反应时间评价视野感知域内三种侧壁涂料对驾驶者视觉功效的影响,从而探索公路隧道照明安全节能的新途径。试验结果表明:使用蓄光反光涂料的公路隧道侧壁可显著提高照明环境亮度;在同种LED灯照明条件下,使用反射率较高且反射光光谱中黄绿光成分较多的侧壁涂料有助于提高驾驶者的视觉功效,从而有利于公路隧道的行车安全和照明节能。     

光导照明系统在隧道工程中的应用试验研究

光导照明系统是一种新型的照明装置,其光源全部取自自然光线,无需任何人工能耗,属真正节能、环保、绿色的照明方式。本文以国内首次应用光导照明系统的上海长江路隧道工程为例,对光导照明系统在隧道工程及地下空间中应用的相关技术进行了试验和研究,拟为节能环保光导照明系统今后在隧道乃至地下空间内大规模应用提供技术支撑。     

隧道加强照明配光优化技术研究

公路隧道照明中相比中间段基本照明而言,加强照明采用传统宽光曲线照明的性价比并不高,较长照射路径反而易造成过多的光通量损耗。为此,本文采用数值模拟的方法对隧道加强照明进行仿真,对比收光型和非收(宽)光型两种配光曲线的照明计算结果,分析收光曲线的照明效能并进一步优化配置。研究结论为:加强照明收光型配光曲线比非收光型配光曲线更节能,当路面平均照度要求为1 500 lx时,非收光曲线照明需求光通量高出收光曲线照明15.8%;收光曲线照明时路面照度总均匀度并不比非收光曲线照明低;对称型收光曲线拱顶单光带布设时,横向偏0.45 m时照明效果最佳。     

“低碳经济”背景下公路隧道照明节能策略

目前我国公路隧道运营照明存在的突出问题主要表现在:照明设计参数有待完善、照明控制方式较为落后、照明节能理念存在误区、照明设施养护未得重视。文章基于建设"环境友好型"公路隧道理念,从系统工程角度提出公路隧道照明节能的15项重要措施,包括准确测试洞外亮度、优化照明设计参数、选择使用节能光源等,基本涵盖公路隧道照明技术性节能、结构性节能、管理性节能的各个方面。工程实践表明,这些技术和措施可实现公路隧道照明综合节能20%以上的总体目标,具有较好的生态效益、经济效益和社会效益。     

隧道照明设计及照明节能的应用

在无锡太湖大道隧道照明设计过程中,采用了先进的绿色节能光源LED,并实现9级亮度调光。介绍了隧道照明光源的选择过程,并对隧道各区段照明控制系统设计和节能效果进行了分析。     

电磁感应无极灯在上海上中路隧道中的应用

电磁感应无极灯是一种新型长寿命的节能光源，上海上中路隧道南线基本照明及加强照明选用了无极灯光源。通过对传统光源及无极灯性能的分析，详细介绍了选用无极灯的原因及整个设计过程，为其它隧道工程的照明设计提供借鉴和参考。     

LED为隧道照明带来安全节能的保障

<正>隧道照明,因为其24小时持续工作以及特别注重安全的特点,对新型节能照明系统的需求强烈。作为节能、长寿命、维护方便的光源和系统,LED的使用不但能提升安全水平,还能够有效降低能源耗费及隧道运营成本。数据显示,仅2010年我国就有10万盏LED隧道灯应用于隧道建设,已取得了良好的社会和经济效应。     

高压钠灯和LED灯在隧道照明中的应用分析

为了探究高压钠灯和LED灯组合照明在隧道照明中的适用性,文章系统梳理了国内外隧道工程照明领域中高压钠灯和LED灯的发展现状、存在的问题及对策及发展前景。目前单独使用LED灯具确实能达到节能减排、低碳环保的效果,但却亮度不足,而考虑到传统隧道照明采用高压钠灯的方案费用高以及单一光源对隧道入口段产生的影响,故将LED灯和高压钠灯组合使用,以发挥两种光源的优点。本文通过文献查阅和调研最终得出在目前高压钠灯向LED灯过渡的发展阶段,组合照明的方式在隧道入口段可以提高可视性,充分发挥两种灯具的优点。     

基于模糊控制决策的隧道照明节能方案研究

为响应国家节能减排的号召,文章以隧道照明系统为节能研究对象,分析隧道照明存在的不合理因素,提出基于模糊控制的隧道照明节能方案,并应用到南宁外环旧村隧道照明系统中,结合考虑影响隧道照明系统的各项因素,优化照明设计和运营管理,实现隧道照明的节能减排。     

隧道LED照明精细化调光控制技术及实证研究

结合理论分析和实际测试,本文提出了一种自适应动态调光隧道LED照明控制技术,对动态调光控制原理进行了理论分析,并与常规的隧道LED分级调光照明和隧道高压钠灯照明的节能成效及投融资进行了全面对比分析,通过对示范工程隧道LED照明系统进行实证分析,表明隧道LED照明精细化调光控制技术在节约建设投资和日常运营节能方面具有显著的优势.该研究成果将为我国高速公路隧道LED照明系统提供一种科学低能耗自适应动态调光控制技术方案.     

Survey of R&D in PRT systems

A survey of research and development in advanced transit has been made by Chalmers University of Technology in Gothenburg in cooperation with Trans21 in Boston. Summary findings are reported for fourteen academic research programs and ten development programs for PRT. An earlier version of this paper was presented at the International Conference of PRT and other Emerging Systems held in Minneapolis in 1996.     

Optimization of bus stop locations for improving transit accessibility

A mathematical model is developed in this paper to improve the accessibility of a bus service. To formulate the optimization model, a segment of a bus route is given, on which a number of demand entry points are distributed realistically. The objective total cost function (i.e. the sum of supplier and user costs) is minimized by optimizing the number and locations of stops, subject to non‐additive users' value of time. A numerical example is designed to demonstrate the effectiveness of the method thus developed to optimize the bus stop location problem. The sensitivity of the total cost to various parameters (e.g. value of users' time, access speed, and demand density) and the effect of the parameters on the optimal stop locations are analyzed and discussed.     

Productive efficiency and ownership of urban bus services

The established ownership mix of urban bus operations in Australia provides a unique opportunity to investigate the productivity differences between public and private bus service supply. Using duality theory in economics which links economic indices of factor productivity to the cost structure of a firm, we develop empirical measures of total and partial productivity of inputs, and adjust the differences for the effects of ownership status and operating environment. The evidence supports the notion that private supply of public passenger transport in general has performed more efficiently in the past than public supply, although the differences in productivity need not continue in the future.     

管道风险分析指数评分法中分值调整初探

管道风险分析指数评分法中重要步骤之一就是确定影响管道事故因素的权重,各个管道风险因素在整个管道事故中所占的权重是不相同的。针对目前管道风险分析指数评分法基本假设之一（各因素的分值范围都是0～100分）,为了更加客观、准确、合理地反映各个风险因素对于管道事故的影响程度,提出并论述了依据层次分析法的数学逻辑性进行综合计算得出管道风险因素的权重,然后对评分法中各个因素的最高分值,根据其权重不同进行相应调整,从而增强评价者对风险因素的认识和评判能力,提高管道风险评价结果的准确性。     

Determinants of modal choice in freight transport

In the next few years, exciting developments in the field of freight transport are likely to occur. The Channel Tunnel will be perceived as giving railways much greater distance of operation, compared to the current train ferry to/from Great Britain. The further development of swap-body technology will allow easier modal transfer and the creation, in 1992, of a single market in Europe will transform the pattern of trade. All of these are likely to have significant impacts on modal choice, and hence modal split, in freight transport. Reappraisal by many firms of the modes of transport used is likely but will it result in a net transfer of freight from road to rail and, if so, to what extent? To answer such questions, an accurate and reliable method of predicting modal split is required. Research in the past has concentrated on the development of modal split models based on generalised costs. These fail to explain adequately the prevalence of road freight in the UK. From surveys of freight managers within industry, it is clear that models to date rely too heavily on the economic cost factor and too little on behavioural factors (Jeffs 1985). This paper derives from a recent study of freight transport modal choice from the standpoint of the transport decision-maker within the firm. It attempts to shed light on the actual parameters which should be incorporated into a modal split model. Many variables appear to exert an influence on modal choice decision-making process. However, it is possible to categorise them into six main groups, namely: customer-requirements; product-characteristics; company structure/organisation; government interventions; available transport facilities; and perceptions of the decision-maker him/herself. It is the interactions and inter-relationships between these which ultimately determine freight modal split. This study has shown that the relationship between the outcome of the transport decision process and the values of particular determinants of modal split is not straight-forward, due to the complexity and variety of interactions involved. Perhaps one of the main reasons for researchers' failure hitherto to develop a successful modal-split model has been the preoccupation with techniques that rely on the development of common metric (e.g. generalised cost), which has led to the exclusion of some important explanatory variables along quite different dimensions. Another important issue concerns the appropriate level of aggregation. In order not to reduce the explanatory power of the key variables, it is important to work at a disaggregate level, although this does make substantial demands on data. The use of factor analysis enables both the aggregation of information without loss of behavioural reality and the specification of variables in terms of a common metric. In conclusion, freight transport has usually been examined within too narrow a framework. It must be placed firmly within the context of the total industrial process. The demand for freight transport is directly influenced by the level, composition and geographical distribution of production and consumption activities. Freight flows are complex and so it is highly unlikely that a universal mode-choice model can ever be developed. Future research should, therefore, be directed towards developing partial models in response to specific needs of those involved in decision-taking in the freight sector.     

A century of evolution of the accessibility concept

The concept of accessibility has acquired numerous meanings along multiple dimensions during the century of its evolution. This essay argues for the salience of two dimensions: application-based and definition-based. In its application, accessibility has incorporated positive and normative dimensions which have varied in prominence over time. In its definition, accessibility has varied between a mode of evaluation incorporating measured mobility and proximity, on the one hand, and a predefined market basket of urbanist improvements to transportation and land use systems, on the other. Advocates of the accessibility shift should emphasize both the measured approach to accessibility and accessibility’s normative side.     

Governing autonomous vehicles: emerging responses for safety,liability, privacy,cybersecurity, and industry risks

ABSTRACT

The benefits of autonomous vehicles (AVs) are widely acknowledged, but there are concerns about the extent of these benefits and AV risks and unintended consequences. In this article, we first examine AVs and different categories of the technological risks associated with them. We then explore strategies that can be adopted to address these risks, and explore emerging responses by governments for addressing AV risks. Our analyses reveal that, thus far, governments have in most instances avoided stringent measures in order to promote AV developments and the majority of responses are non-binding and focus on creating councils or working groups to better explore AV implications. The US has been active in introducing legislations to address issues related to privacy and cybersecurity. The UK and Germany, in particular, have enacted laws to address liability issues; other countries mostly acknowledge these issues, but have yet to implement specific strategies. To address privacy and cybersecurity risks strategies ranging from introduction or amendment of non-AV specific legislation to creating working groups have been adopted. Much less attention has been paid to issues such as environmental and employment risks, although a few governments have begun programmes to retrain workers who might be negatively affected.     

Real-world gaseous and particle emissions of a Bi-fuel gasoline/CNG Euro 6 passenger car

The objective of the present study is the assessment of the environmental impact of a bivalent (bi-fuel) vehicle, running either on gasoline or compressed natural gas (CNG). To that aim, a Euro 6 passenger car was tested under various real-world driving conditions. In order to cover the full range of conventional powertrains currently in the market, the tests were also repeated on a Euro 6 diesel passenger car. Both cars were driven in two routes, the first complying with the regulation limits and the second going beyond them. Carbon monoxide (CO), nitrogen oxides (NO_x) and particle number (PN) emissions were recorded using a Portable Emissions Measurement System (PEMS). Apart from the aggregated emission levels, in g/km, the exact emission location along the route was also assessed. Natural gas proved beneficial for CO and PN emissions, the level of which always remained below the respective legislation limits. On the other hand, under the dynamic driving conditions with gasoline, the relevant limits were exceeded. Cold start, occurring at the beginning of the urban part, and motorway driving were identified as major contributors to total emissions, especially in gasoline mode. However, the application of natural gas was associated with a penalty in NO_x emissions, which were significantly increased as compared to gasoline. Local peaks within the urban part were identified in CNG mode. In any case, the diesel vehicle was by far the highest NO_x emitter.