Links Of Road Network Research Articles

Developing a fuzzy bi-objective programming and MCDM model for bridge maintenance strategy optimization

Bridges serve as critical links in road networks, requiring continuous maintenance to ensure proper functionality throughout their lifespan. Given their pivotal role in the urban landscape, connecting various parts of a city, this research presents a multi-objective optimization model for the maintenance and repair of bridges in Babolsar, Iran. The model takes into account budget constraints and aims to minimize the total life cycle and user costs, encompassing traffic delays and vehicle expenses, while maximizing the reliability of the bridge network. Recognizing the inherent complexity of this problem, a multi-objective particle swarm optimization algorithm has been developed for an accurate solution. The study further conducts sensitivity analysis on the objective function concerning the available budget, evaluating key parameters such as hourly costs and the time value of vehicles. The results show that with an increase in the budget level, the number of repairs related to the most costly maintenance has significantly risen. In other words, as the budget expands, the model tends to favor repairs with higher costs because their impact on the bridge’s performance is more substantial.

Urban traffic assignment based on signalized intersection delays

Existing methods to determine travel time on the road network links are based on the estimation of link saturation. Different formulas are used during the estimation but the ratio of traffic volume to link capacity is always the base for calculations. The main problem of such an approach is an insufficient justification of the lane capacity value which defines link capacity. It causes doubts about the background of the approach application regarding urban traffic flows. At the same time, authoritative traffic management guidelines declare that when there are signal-controlled intersections on the link then the link capacity is restricted by the intersection with minimal capacity. Thus, the alternative to the known traffic assignment approach based on link capacity can be created and then used to make the assignment on the base of delays at intersections. Evaluation of such an alternative is the actual task as the new approach to traffic assignment opens the scope for improving the accuracy of modelling the traffic flows in cities. Goal. The new approach to traffic assignment on the base of intersection delays needs to be tested for the usefulness for transport modelling practice. Methodology. The alternative approaches to traffic assignment were experimentally compared based on the parameters of the transport model, which provide the compliance of the calculated average vehicles’ speed with the factual one. Results. The new approach to traffic assignment based on intersection delays allows a more accurate calculation of traffic volumes. Originality. The new approach to traffic assignment based on intersection delays allows avoiding the need to set restrictions on road network links’ capacity. Practical value. Received results clarify the way to set the free-flow travel time of network objects in VISUM and allow increasing accuracy of urban traffic flows modelling

Practice Friendly Metric for Identification of Critical Links in Road Networks

Despite the important planning value of transportation link criticality, the existing methodologies are mostly in the academic domain, and require in-depth technical skills and extensive data. The most common approach to identify critical links in transportation networks is to remove each link iteratively, conduct traffic assignment, and assess the criticality of each link based on the consequences of its removal. Since conducting multiple traffic assignment is costly for large networks, the authors of this paper recently introduced the link criticality index (LCI). The LCI utilizes the iterations in the Frank–Wolfe solution of the user equilibrium (UE) problem to provide link criticality ranking within a single traffic assignment. The LCI was shown to provide balanced rankings with respect to alternative routes as well as the link flows. However, the LCI is not practice-friendly because of the technical knowledge and data needed to run traffic assignments. Accordingly, this paper introduces a practice friendly link criticality index (PF-LCI). PF-LCI relaxes some of the technical requirements and uses some expert knowledge input data to provide “top” link criticality rankings that are consistent with the LCI. PF-LCI utilizes the network flow instances at different times of day instead of iterations of UE assignment solution. Expert knowledge input is sought for the major origin–destination pairs (ODs) and the viable routes between the selected ODs. The method is implemented on a small sample network and the Sioux Falls network to test PF-LCI’s capabilities. Results show that PF-LCI produces accurate rankings for the top critical links that are most relevant to practitioners’ concerns.

Identification of critical links in a large-scale road network considering the traffic flow betweenness index.

The traditional full-scan method is commonly used for identifying critical links in road networks. This method simulates each link to be closed iteratively and measures its impact on the efficiency of the whole network. It can accurately identify critical links. However, in this method, traffic assignments are conducted under all scenarios of link disruption, making this process prohibitively time-consuming for large-scale road networks. This paper proposes an approach considering the traffic flow betweenness index (TFBI) to identify critical links, which can significantly reduce the computational burden compared with the traditional full-scan method. The TFBI consists of two parts: traffic flow betweenness and endpoint origin–destination (OD) demand (rerouted travel demand). There is a weight coefficient between these two parts. Traffic flow betweenness is established by considering the shortest travel-time path betweenness, link traffic flow and total OD demand. The proposed approach consists of the following main steps. First, a sample road network is selected to calibrate the weight coefficient between traffic flow betweenness and endpoint OD demand in the TFBI using the network robustness index. This index calculates changes in the whole-system travel time due to each link’s closure under the traditional full-scan method. Then, candidate critical links are pre-selected according to the TFBI value of each link. Finally, a given number of real critical links are identified from the candidate critical links using the traditional full-scan method. The applicability and computational efficiency of the TFBI-based approach are demonstrated for the road network in Changchun, China.

Structural Elements of Habitable Bridges

This article examines a building type having a long-span aboveground structure also known as a habitable bridge. Habitable bridges provide a useful solution for a number of transportation system limitations and social problems in the urban planning process. Contemporary cities, including Moscow, face problems originating from current structure and missing links in road networks. The missing links appear when an extended barrier such as: a river, a ravine, a highway and railroad track crosses the road. In such cases, habitable bridges serve as vehicle and pedestrian links across these barriers and connect residential, business, cultural and industrial city boroughs. They also offer other feature areas besides a transit function. In this study the author describes the idea of additional feature facilities and operating conditions for habitable bridges in big cities. An investor’s active engagement in the design and building process is key for a successful and productive outcome. In order to attract private investors it is necessary to offer useful commercial areas within the habitable bridge development. Increasing the bridge height to accommodate additional area is one of many ways to provide attractive incentives for investors. General criteria requirements are addressed through standardized construction solutions. One of the most suitable solutions to interconnect local interborough links is with a «short-span habitable bridge». This study addresses the structural components of the habitable bridge building type and its relationship to the road network as well as the surrounding city framework.

Data-driven Bicycle Network Analysis Based on Traditional Counting Methods and GPS Traces from Smartphone

This research describes numerical methods to analyze the absolute transport demand of cyclists and to quantify the road network weaknesses of a city with the aim to identify infrastructure improvements in favor of cyclists. The methods are based on a combination of bicycle counts and map-matched GPS traces. The methods are demonstrated with data from the city of Bologna, Italy: approximately 27,500 GPS traces from cyclists were recorded over a period of one month on a volunteer basis using a smartphone application. One method estimates absolute, city-wide bicycle flows by scaling map-matched bicycle flows of the entire network to manual and instrumental bicycle counts at the main bikeways of the city. As there is a fairly high correlation between the two sources of flow data, the absolute bike-flows of the entire network have been correctly estimated. Another method describes a novel, total deviation metric per link which quantifies for each network edge the total deviation generated for cyclists in terms of extra distances traveled with respect to the shortest possible route. The deviations are accepted by cyclists either to avoid unpleasant road attributes along the shortest route or to experience more favorable road attributes along the chosen route. The total deviation metric indicates to the planner which road links are contributing most to the total deviation of all cyclists. In this way, repellant and attractive road attributes for cyclists can be identified. This is why the total deviation metric is of practical help to prioritize bike infrastructure construction on individual road network links. Finally, the map-matched traces allow the calibration of a discrete choice model between two route alternatives, considering distance, share of exclusive bikeway, and share of low-priority roads.

Road Network Rating Based on Land Use of Pokhara

Road Network Analysis considering land use has high potential uses in our country, where the coordination between land use and transportation planning is lacking in many aspects. This research proposes road network analysis based on land use for the current road network of old Pokhara city, one of the urbanizing cities that have led to the rapid urbanization recently. The road network in this city needs to be evaluated to develop efficient and better transportation facility. This study uses Geographic Information System (GIS) to create network database and analyze the current road network based on land use pattern and road attribute, identifying the worst area for transportation supply. This study further evaluates the road network with network volume capacity ratio of the same road section. Rating analysis along with network volume capacity evaluation has provided clear understanding of the links of road network on ward no 8 of Pokhara city having problem with traffic coordination. Among the major roads of the ward 8, Nayabazar road section is found in an unacceptable Level of Service (LOS) but other roads along with the highway passing are within the acceptable limit of LOS.

Health Problems in Zvimba Rural and Communal Areas in Zimbabwe

This study was carried out to determine people’s health problems in Zvimba district in Mashonaland West Province. The research employed the survey research design to solicit data since it was found to be the most appropriate for this study as it was capable of capturing the respondents’ views towards health issues in Zvimba district fast enough to meet both the time frame and the demands of the study. It involved 189 participants in an easily definable geographical area. These respondents comprised 135 communal dwellers who visited clinic or hospital the same day one of the researchers passed through the clinic or the hospital collecting data for the study, plus 54 professional health workers who accepted to participate in the study. The study used questionnaires and interviews for the collection of data. Research results showed that malaria and diarrhoea were the most prevalent diseases with the highest frequency rates among other diseases. The study recommends increase in the number of clinics, availability of low cost public transport, upgrade of road network links and community engagement in health awareness programmes. Keywords : People, health, health problems, rural, communal, Zvimba, Zimbabwe DOI : 10.7176/DCS/9-4-09 Publication date : April 30 th 2019

Predicting the probability of failure of timber bridges using fault tree analysis

The resilience of a community in an extreme event depends mainly on the robustness of the critical infrastructures. Road bridges are a critical link of the road network, which plays a focal role in Australia’s economy, prosperity, social well-being and quality of life. Timber bridges are a weaker link of the Australian road network and they often provide critical access to the rural communities. This research uses a number of bridge inspection reports to develop a method to predict the probability of failure of a timber bridge. The inspected condition states of the elements in the timber bridge are used to develop a Markov chain based model and Gamma process model to predict the deterioration of each element. The probability of condition state movement for each element thus calculated were used in fault tree analysis to estimate likelihood of failure of a bridge in a given time period. Although the developed method is based on limited data and it has several limitations, model can be further refined with the availability of more inspection reports. The method developed is demonstrated using an inspection report for a timber bridge, which was not used in the development of the models.

基于含权Newman算法的交通控制子区划分

为使交通网络控制子区内的交通流具有更好的同质性，本文将道路网络中的路段抽象为点，相邻路段之间的连接关系抽象为边，形成一个对偶的网络拓扑结构图。以用户均衡交通分配得到的路段交通流数据除以路段长度计算得到路段的“拟交通密度”；通过引入路段拟交通密度，扩展了Newman子区划分算法。最后，选取实际路网、以NSK (Normalized cut Silhouette)指标验证K均值聚类算法、传统Newman算法和扩展的Newman子区划分算法的优劣。研究发现：传统K均值聚类算法得到的各子区NSK指标和路网NSK指标都相对最小，但同一个子区内的路段在空间位置上不相连，没有实际运用价值；扩展的Newman子区划分算法的NSK值优于传统Newman快速划分算法，证实引入了路段拟交通密度作为边权，使得划分出来的结果更加符合交通网络的特性。 A dual network is structured firstly by setting link of road network as dual node and incidence relationship between links of road network as dual links in the dual network in order to keep homogeneity of traffic flow in each road sub-network partitioned. Link traffic flow, which is the result of traffic demand assignment based on user equilibrium principle, is divided by link length and then the definition of quasi traffic density of each link is proposed secondly. Newman network partition algorithm is extended by introducing the definition of quasi traffic density. Thirdly, the superiority of K-means cluster algorithm, Newman network partition algorithm and extended Newman network partition algorithm are identified by measurement of Normalized cut Silhouette (NSK) on a real road network. This study has identified that: indexes value NSK and NSK on networks of traditional K-means cluster algorithm are relatively small, but the sub-network partitioned is not connected in the space so that it lacks practical value. Index NSK of extended Newman network partition algorithm is prior to that of Newman network partition algorithm. The sub-network which is partitioned by extended Newman network partition algorithm introduced the definition of quasi traffic density is favorable for purpose of traffic flow control.

Enhanced Map-Matching Algorithm with a Hidden Markov Model for Mobile Phone Positioning

Numerous map-matching techniques have been developed to improve positioning, using Global Positioning System (GPS) data and other sensors. However, most existing map-matching algorithms process GPS data with high sampling rates, to achieve a higher correct rate and strong universality. This paper introduces a novel map-matching algorithm based on a hidden Markov model (HMM) for GPS positioning and mobile phone positioning with a low sampling rate. The HMM is a statistical model well known for providing solutions to temporal recognition applications such as text and speech recognition. In this work, the hidden Markov chain model was built to establish a map-matching process, using the geometric data, the topologies matrix of road links in road network and refined quad-tree data structure. HMM-based map-matching exploits the Viterbi algorithm to find the optimized road link sequence. The sequence consists of hidden states in the HMM model. The HMM-based map-matching algorithm is validated on a vehicle trajectory using GPS and mobile phone data. The results show a significant improvement in mobile phone positioning and high and low sampling of GPS data.

Alternative network robustness measure using system-wide transportation capacity for identifying critical links in road networks

In transportation planning works, critical links identification is helpful to evaluate the vulnerable parts of the designed network schemes. A new capacity-based network robustness index is presented for identifying critical links and evaluating the transportation system performance. It uses the change of the total network capacity as an evaluation measure. The advanced practical network capacity model is employed to estimate the throughput of transportation system. A sensitivity analysis based algorithm is also developed to solve the practical capacity model efficiently. The capacity-based network robustness index identifies the links which play critical roles in the transportation capacity of the whole network. The capacity-based network robustness index is an effective supplementary to the existing network evaluation indices. The experiments demonstrate the differences between the capacity-based network robustness index and the efficiency-based network robustness index. The capacity-based network robustness index can be used as a practical measure in the situations where the network robustness index is not significant.

An identification model of urban critical links with macroscopic fundamental diagram theory

How to identify the critical links of the urban road network for actual traffic management and intelligent transportation control is an urgent problem, especially in the congestion environment. Most previous methods focus on traffic static characteristics for traffic planning and design. However, actual traffic management and intelligent control need to identify relevant sections by dynamic traffic information for solving the problems of variable transportation system. Therefore, a city-wide traffic model that consists of three relational algorithms, is proposed to identify significant links of the road network by using macroscopic fundamental diagram (MFD) as traffic dynamic characteristics. Firstly, weightedtraffic flow and density extraction algorithm is provided with simulation modeling and regression analysis methods, based on MFD theory. Secondly, critical links identification algorithm is designed on the first algorithm, under specified principles. Finally, threshold algorithm is developed by cluster analysis. In addition, the algorithms are analyzed and applied in the simulation experiment of the road network of the central district in Hefei city, China. The results show that the model has good maneuverability and improves the shortcomings of the threshold judged by human. It provides an approach to identify critical links for actual traffic management and intelligent control, and also gives a new method for evaluating the planning and design effect of the urban road network.

Pricing and Internalizing Noise Externalities in Road Freight Transportation

Abstract People living close to main roads may suffer from the nuisance of traffic and noise pollution. This paper assesses the effect of full routing cost in vehicle routing decisions by internalizing the external cost of noise. On a first step, noise externalities are economically assessed through a contingent valuation procedure. Secondly, a novel methodology is proposed to allocate the external costs to the road network links. Results show significant differences in routing planning depending on the approach: minimization of traditional internal cost versus minimization of full cost. These results encourage further research in pricing and methodologies to internalize externalities.

Indicators of reliability and vulnerability: Similarities and differences in ranking links of a complex road system

This article investigates two performance attributes of road networks, reliability and vulnerability, analyzing their similarities as well as the differences that justify distinct definitions, based on consolidation of recent studies. We also discuss the indicators found in the literature for these two performance attributes. Since various authors treat vulnerability as an aspect of reliability instead of a specific attribute, we carried out an application to a complex road network representative of the city of Rio de Janeiro to check the suitability of this approach. The results show that the vulnerability indicators are more strongly affected by the characteristics of alternative routes while the reliability metrics are more sensitive to the congestion level. The conclusion is that reliability and vulnerability should be treated distinctly for evaluating the performance of road network links.

Improving vehicle speed estimates using street network centrality

ABSTRACTThis paper describes a novel approach to improve prediction models which estimate vehicle speeds and their diurnal variation for road network links in urban street networks using only static map attributes. The presented approach takes into account previously neglected spatial information by integrating network centrality measures for closeness (indicating how central a link is) and betweenness (indicating how important a road link is) into the prediction model. The model is calibrated with a real-world dataset of 100 million individual speed measurements from a fleet of 3500 taxi probe vehicles in Vienna, Austria. Given that centrality can be derived directly from readily available street network data, the experimental results demonstrate that integrating centrality measures considerably improves the predictions without the need for adding a supplementary data source. Improvements for vehicle speed estimates are particularly prevalent on important street network links in the city center as well as rural streets in the periphery.

Traffic State Interpolation of Unobserved Road Links by Accumulated Data Using the Relationships of Links in Road Network

Traffic State Interpolation of Unobserved Road Links by Accumulated Data Using the Relationships of Links in Road Network

English

A growing concern for public transit is its inability to shift passenger’s mode from private to public transport. The transit route network design (TRND) problem seeks a set of bus routes and schedules that is optimal in the sense that it maximizes the utility of an urban bus system for passengers while minimizing operator cost In this paper various data is collected to finding an optimal route length of VTCOS bus’s selected route, passenger capacity, total trip, boarding and alighting survey of passenger. TRANSCAD software provides useful tools such as road network links, shortest paths, O-D Matrices. This paper present some route of Anand city are very low passenger, so running empty buss and some route heavy passenger so increase in number of busses is advised. Our study area suggested route no. 2 & 7 is more reliable and suitable optimization route for the public transportation system.

Evaluating the Prioritization of Transportation Network Links under the Flood Damage: by Vulnerability Value and Accessibility Indexs

Flood does not leave equal impacts on the transportation network links. Each link of the network demonstrates a different level of resistance against flood based on its hydrologic and structural design. The purpose of the present investigation is to determine vulnerability value and merge that with the accessibility index for strengthening the transportation network links against flood. The Golestan province was chosen as the case study. In this study, for evaluating of vulnerability value, the flood peak was determined based on the maximum daily discharge. In order to assess the flood peak for different return period's frequency analysis (HYFA) software was used. Finally, the vulnerability value as a result of destruction of the bridges due to flood was determined. For evaluating accessibility indexs, the roads network was modeled by EMME2 software and then, the network was loaded based on travel time and traffic volume. The accessibility indexs based on the travel time and traffic volume was determined and assessed before and after flood. The vulnerability value is utilized as a coefficient for the accessibility indexs in the study. According to the obtained values, the prioritizations of the different network links were prioritized in the occurrence of flood. Evaluation of prioritization of different links of road network has been determined based on vulnerability value multiplied by accessibility index. Generally, it can be concluded that merely using the accessibility index does not suffice in prioritizing the transportation network links against flood. Consequently, another index needs to be assessed simultaneously with the accessibility index. This index is in fact the vulnerability value of the destruction of the bridge due to flood. In the composed index, a merged form of these two proposals has been presented. Key word: accessibility indexes, bridges, flood peak, return period, vulnerability value, traffic volume and travel time

CLASS: A City Logistics Analysis and Simulation Support System

The paper presents a City Logistics Analysis and Simulation support System (CLASS) for the identification of critical stages and the simulation of city logistics scenarios. The analysis of current scenario focuses on logistics and freight transport in relation to land use, freight restocking demand and supply, logistic profile and road network performances and impacts. The simulation is able to point out the relations existing among city logistics measures, decision-maker choice dimensions by using a multi-stage demand model and a discrete choice approach for each decision level. Among the outputs, the freight vehicle flows on the road network links allow to compute the link performances in terms of congestion, pollution and road accidents involving freight vehicles. An application of the support system to the freight restocking for the inner area of Rome is presented.