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971.
972.
为将西柏坡公路修建成一条生态环保的红色旅游路,在设计阶段,合理设置桥梁隧道及因地制宜的将路基上下行分离,并采取科学的排水防护设计及符合实地条件的绿化措施,为工程建设打下良好的基础。 相似文献
973.
Takeo Ihara 《国际交通安全学会研究报告》2011,34(2):94-102
The aim of this paper is to explain why we have conducted “Traffic Safety Education” in the Kagawa Prefecture during the past ten years so as to clarify the important factors for preventing painful traffic accidents in advance. To meet this aim, we firstly clarify the reason why we eventually decided to conduct “Traffic Safety Education” in the Kagawa Prefecture. In other words, the organization of powerful actors and/or leaders to cope with traffic accidents plays a very important role in “Traffic Safety Education.” Then, we specifically describe the essential parts of our “Traffic Safety Education”. In this respect, we have decided to select the following two aims: to reduce the number of traffic accidents, and to improve traffic manners, respectively. Thirdly, we evaluate various measures, such as teaching materials, teaching methods, and other activities of our “Traffic Safety Education” in detail. Lastly, we summarize the remaining tasks, which have been revealed so far, together with some concluding remarks. 相似文献
974.
975.
泥岩是由粘土矿物固化而成的沉积岩,多具有膨胀性,对隧道和路堑工程有较大的影响。对兰武铁路永登地区泥岩工程特性进行了初步研究,阐述了泥岩的物质构成、物理力学指标,分析了泥岩的膨胀特性,并提出了针对性的工程措施和建议。 相似文献
976.
Carlos F. Daganzo 《Transportation Research Part B: Methodological》2011,45(5):782-788
A simple model of traffic flow is used to analyze the spatio-temporal distribution of flow and density on closed-loop homogeneous freeways with many ramps, which produce inflows and allow outflows. As we would expect, if the on-ramp demand is space-independent then this distribution tends toward uniformity in space if the freeway is either: (i) uncongested; or (ii) congested with queues on its on-ramps and enough inflow to cause the average freeway density to increase with time. In all other cases, however, including any recovery phase of a rush hour where the freeway’s average density declines, the distribution of flow and density quickly becomes uneven. This happens even under conditions of perfect symmetry, where the percentage of vehicles exiting at every off ramp is the same. The flow-density deviations from the average are shown to grow exponentially in time and propagate backwards in space with a fixed wave speed. A consequence of this type of instability is that, during recovery, gaps of uncongested traffic will quickly appear in the unevenly congested stream, reducing average flow. This extends the duration of recovery and invariably creates clockwise hysteresis loops on scatter-plots of average system flow vs. density during any rush hour that oversaturates the freeway. All these effects are quantified with formulas and verified with simulations. Some have been observed in real networks. In a more practical vein, it is also shown that the negative effects of instability diminish (i.e., freeway flows increase) if (a) some drivers choose to exit the freeway prematurely when it is too congested and/or (b) freeway access is regulated in a certain traffic-responsive way. These two findings could be used to improve the algorithms behind VMS displays for driver guidance (finding a), and on-ramp metering rates (finding b). 相似文献
977.
978.
管道运输是石油生产输送中一种重要的运输方式,其运行的安全可靠性已经引起了高度的重视.介绍了管道的腐蚀机理,分析了影响腐蚀的因素,从内、外防腐蚀,阴极保护等方面论述了防腐蚀的应对措施.为了对输油管道的腐蚀速率进行预测,掌握输油管道腐蚀的基本规律,介绍了几种常用的油气集输管道腐蚀速率预测研究方法,为今后石油运输管道腐蚀的研... 相似文献
979.
当前我国已步入老龄社会,城市交通系统面临着新的挑战。文中从老龄化社会面临的交通问题出发,在总结老年群体出行特征基础上,分析目前城市交通系统存在的一些问题。同时参考国外经验,对处于老龄化社会的城市交通系统从公共交通的发展、无障碍设施的建设、老年人安全意识的教育及驾驶员培训和审验制度的完善等几个方面提出了对策和建议。各相关部门应着力推进适应老龄社会的城市交通系统的建设,维护老年人交通权益,进一步提高我国城市交通对社会老龄化的适应性。 相似文献
980.