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101.
A study of the influence of severe environmental conditions on common traffic congestion features 下载免费PDF全文
On the basis of real traffic and environmental data measured on German freeways, we studied common features of traffic congestion under the influence of severe weather conditions. We have found that traffic features [J] and [S] defining traffic phases “wide moving jam” (J) and “synchronized flow” (S) in Kerner's three‐phase theory are indeed common spatiotemporal traffic features. The quantitative parameters for both traffic phases [S] and [J] were investigated in a comparison of “ideal” weather conditions (good visibility and no precipitation) and severe weather situations (icy road, wind, precipitation, etc.). We showed spatiotemporal congested patterns in several space–time diagrams based on the Automatic Tracking of Moving Jams/Forecasting of Traffic Objects (ASDA/FOTO) model reconstruction for roadside detectors. A statistical study of traffic phase [J] parameters was presented, showing the average values and standard deviation of the quantities. Similarities and differences were analyzed, and some consequences for vehicular applications were discussed to cope with severe weather conditions. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
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本文将长江口水域有关水文气象、助航标志和船舶交通管理规定等做一总结介绍,并结合二起事故案例分析,探讨船舶在此水域的航行安全管理,以利航经长江口水域船舶的安全。 相似文献
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针对荆江河段岸坡渗流破坏情况,结合破坏案例分析岸坡渗流破坏原因,确定岸坡渗流破坏主要影响因素——地质因素、水文因素和降水因素。荆江河段岸坡地质结构主要分为3类,即单一砂性土地质结构、上黏性土下砂性土双层地质结构以及由黏性土和砂性土组成的互层、夹层等结构土体。荆江河段地下水和江水补给关系复杂——汛期江水补给地下水,枯水期地下水补给江水。三峡蓄水后,汛后退水速度进一步加快,地下水和江水之间的渗流坡降进一步增加。荆江河段强降水天气分布出现频次和范围仍较高。在此基础上,进一步揭示高滩守护工程区域岸坡渗流破坏机理。 相似文献
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Estimating freeway route travel time distributions with consideration to time‐of‐day,inclement weather,and traffic incidents 下载免费PDF全文
This paper develops an efficient probabilistic model for estimating route travel time variability, incorporating factors of time‐of‐day, inclement weather, and traffic incidents. Estimating the route travel time distribution from historical link travel time data is challenging owing to the interactions among upstream and downstream links. Upon creating conditional probability function for each link travel time, we applied Monte Carlo simulation to estimate the total travel time from origin to destination. A numerical example of three alternative routes in the City of Buffalo shows several implications. The study found that weather conditions, except for snow, incur minor impact on off‐peak and weekend travel time, whereas peak travel times suffer great variations under different weather conditions. On top of that, inclement weather exacerbates route travel time reliability, even when mean travel time increases moderately. The computation time of the proposed model is linearly correlated to the number of links in a route. Therefore, this model can be used to obtain all the origin to destination travel time distributions in an urban region. Further, this study also validates the well‐known near‐linear relation between the standard deviation of travel time per unit distance and the corresponding mean value under different weather conditions. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
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可变限速控制可减小降雨导致的高速公路交通拥堵和事故风险.提出雨天高 速公路可变限速控制策略,对经典的元胞传输模型进行改进,构建适用于雨天可变限速 控制问题的高速公路动态交通流模型;在综合考虑交通安全和效率基础上,建立雨天环 境下高速公路可变限速控制方法和模型.实验结果表明,与固定限速相比,雨天可变限速 控制下高速公路平均速度增加了9.3%,车辆总行驶时间减少了11.7%,相邻路段最大车 速差从17.5 km/h 减小为9.4 km/h,降幅达46.3%,有效地提高雨天环境下高速公路通行效 率和安全性. 相似文献
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基于车辆跟驰理论,提出一种车流控制方式,并结合车间距与车辆安全的影响因素,推导得出恶劣天气下能见度与高速公路安全行车速度的关系,可为恶劣天气条件下高速公路的不间断安全运营提供可能。 相似文献
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