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Network topology is the basic for the development of traffic management and control. In a road network, bayonets with installation of surveillance facilities are key components to recognize traffic congestion from time to time. Therefore, identifying the essential bayonets in a road network becomes one of the most efficient ways to alleviate traffic congestion for traffic engineers and transport department. To do so, this paper aims to propose a novel sorting algorithm based on similarity measurements and traffic flow information to efficiently identify key bayonets in road networks. Our research results show that by analyzing the bayonet data in a fixed period of time in a medium-sized city of China, we have successfully identified the location of key bayonet points. Most of these key bayonet points are closed to residential areas and important traffic stations. The rank of these bayonet points can help the city managers better understand the topological characteristics of the road network as well as the propagation of congestion so as to make the traffic policies or control strategies for traffic congestion alleviation. [ABSTRACT FROM AUTHOR]

For long-span cable-stayed bridges, cables serve as one of the most important components to guarantee structural integrity. Forces of stay cables indicate not only the performance of cables themselves but also the overall condition of bridges. In order to help stakeholders to make maintenance decisions, an extreme cable force estimation method was proposed based on cable force measurements and traffic data from the weighing system. First, raw monitoring data were preprocessed based on a median filtering to obtain usable cable force signals. The multiresolution wavelet method was used to extract traffic-induced force component from mixed signals. Then, a Monte Carlo-based random vehicle model was developed using traffic data from the weighing system. Based on field temperature measurements and simulation of traffic-induced effects, extreme cable forces with respect to vehicle loads and temperature effects were predicted by extreme value theory. The Generalized Pareto Distribution (GPD) was adopted to establish the probability distribution models of the daily maximum cable force. Then, the extreme value within a return period of 100 years was determined and compared with the design loading demand. Finally, the effectiveness of the proposed method was validated through a cable-stayed bridge in China. As a result, the low-frequency varying component of cable force response had positive correlation with environmental temperatures, and the extreme value of the predicted cable force under prospective traffic volumes was within limit interval value according to the design code. The conclusions can be utilized by bridge owners to make maintenance decisions. [ABSTRACT FROM AUTHOR]

Accuracy measurement of traffic engineering waste slag in mountainous area is always a basic scientific problem of spoil ground stability estimation. On basis of traffic engineering spoil ground working feature and solid waste characteristics of waste slag, the representative problems' root of sampling and test was discussed. According to practical engineering, a simple practical classification and estimation method was studied. The main conclusions are following. CD Solid waste characteristics, such as large difference in particle size range, uneven spatial distribution of particles and complex sources of waste slag, result in their sampling and test result representative problems; multi-stage slope angle measurement and particle analytical test can be used to replace common experiments of waste slag slope, which solves the above two representative problems. 1 Ratio of coarse and fine (k) is defined as coarse particles gravity divided by fine particles gravity, which divides waste slag into fine grain, mixed grain and coarse grain. 2According to the ratio of coarse and fine, natural repose angle and reshaping slope ratio, the traffic engineering waste slag in mountainous area of Southwest China can be classified into the above three types; the fine grain waste slag's k is less than 0 . 3, natural repose angle being less than 31. 5°, reshaping slope ratio being less than 1. 00 : 2. 00; t he mixed grain waste slag's k is larger than 0. 3 and less than 1. 0, natural repose angle being larger than 31. 5° and less than 3 9. 5°, reshaping slope ratio being larger than 1. 00 : 2. 00 and less than 1. 00 : 1. 50; the coarse grain waste slag's k is larger than 1. 0, natural repose angle being larger than 39. 5°, reshaping slope ratio being less than 1. 00 : 1. 50. 3The methods combined multi-stages slope angle measurement, particle analytical test and slope stability co efficient formula for non-cohension soil, which are presented to replace common test and waste slag slope stability estimation method, are simple and conservative, and can be used in traffic engineering waste slag slope stability estimation and safety control. [ABSTRACT FROM AUTHOR]

With the increasing demand for chemical products in China, how to manage the risks associated with hazardous freight transportation has attracted arising attentions from both government and industry practitioners. From the perspective of carrier companies, transportation modal choice and routing for hazardous freight transportation need to be carefully designed, which motivates current research. This paper aims to optimize the service mode and routing for hazardous freight transportation in a rail-truck network with bi-objectives optimization approach. Several practical concerns are addressed, including the coordination of rail transportation which has fixed train running plan and road transportation which is flexible and mobile, and the consideration of alternative path when the expressway is temporally blocked for hazardous freight due to the traffic restriction measurements on inter-city road segments. Furthermore, the time-varying transportation risks and costs associated with accidents of hazardous freight transportation are investigated. The Max-Min Ant-colony Algorithm (MMAS) algorithm is adopted for solution. For model validations and conclusion generalization, this paper implements a real-life case study in Beijing-Tianjin-Hebei region in China with the objective of minimizing transportation risks and costs. The solutions show that traffic restrictions have an adverse impact on the carrier and alternative paths are able to help the carriers further optimize their routing strategy. A careful consideration and appropriate processing of differences in operational characteristics of two transportation modes, is able to provide a better and more realistic understanding of rail-truck hazardous freight transportation problem. [ABSTRACT FROM AUTHOR]

• We investigate the impacts of HSR entry on air cargo traffic in China. • We quantify the distance level impacts of HSR entry on air belly-hold cargo traffic. • We utilize Chinese air cargo traffic data from January 2011 to December 2017. • The impacts of HSR on belly-hold cargo traffic are stronger among medium-haul flights Freighter cargo volumes and frequencies increase after the entry of HSR. Air cargo is vital to the modern supply chain because it provides efficient and timely delivery. In the past decade, the development of high-speed rail (HSR) in China has resulted in significant impacts on air cargo traffic, which has long been neglected by the existing studies. In this research, we quantify such impacts using HSR entry dummy variables and employ a panel regression approach to capture the impacts, specifically, the impacts on air cargo volumes and flight frequencies. We conduct a case study using quarterly air cargo traffic data in China, which contains 321 city pairs and spans between January 2011 and December 2017. We separately analyze the impacts on belly-hold cargo (carried by combi or passenger aircraft) traffic and freighter cargo (carried by freighters) traffic. We first capture the general impacts on belly-hold cargo traffic and freighter cargo traffic for all city pairs. Then, to quantify the distance level impacts on belly-hold cargo traffic, we categorize city pairs into multiple groups according to their distance and apply the panel regression approach in each group. Our main results include: (1) The entry of HSR services reduces the belly-hold cargo volumes and flight frequencies by 21.9% and 19.4%, respectively; (2) The strongest impacts on belly-hold cargo volumes and flight frequencies are observed in the medium-haul group within a distance of 800–1300 km; (3) After the entry of HSR services, the cargo volumes and flight frequencies of freighter cargo generally increase by 22.3% and 20.9%, respectively; (4) The whole air cargo traffic in the measurement of cargo volumes and flight frequencies decreases after the entry of HSR, and the impacts on whole air cargo volumes are relatively smaller than the belly-hold cargo volumes in the short-haul (no more than 800 km) and long-haul (more than 1300 km) groups. [ABSTRACT FROM AUTHOR]

Hierarchy is an important property of a street network, which suggests that only a small number of streets are prominent. A previous empirical study of a European city has identified four levels of scale in a street network, namely the top 1%, top 20%, bottom 80%, and bottom 20%. This paper investigates such street hierarchies in a large Asian city, Wuhan, with a complicated network of streets. Based on network analysis, we find that street hierarchies in this case study are slightly different so that the fourth scale is adjusted from the initial 20 to 25%. The detected street hierarchies are further compared to the intensity of large-scale traffic flows at different time scales. We find that distributions of both daily and hourly traffic conform well to the street hierarchies. More specifically, the 20% of top streets accommodate about 98% of traffic flow, and the 1% of top streets account for more than 60% of traffic flow. Moreover, this finding indicates that the current street network of Wuhan needs to be improved because the top 20% of streets are rather overburdened leading to traffic congestion. Our study not only provides new quantitative evidence as to the emergence of street hierarchies but also highlights the possible traffic congestion. [ABSTRACT FROM AUTHOR]