Urban Traffic System Research Articles

Transit Signal Priority Controlling Method Considering Non-Transit Traffic Benefits and Coordinated Phase States for Multi-Rings Timing Plan at Isolated Intersections

Transit signal priority (TSP) is a typical strategy used to reduce the delay in public transit and it has been used extensively to improve the transit operations in urban traffic systems. This paper proposes a transit signal priority controlling method considering both the non-transit traffic benefits and the coordinated phase states for multi-ring time plan. The integer linear programming method is used to build the green time extension and red time truncation models. In the proposed model, the optimization object includes two levels: the maximum priority effect for the first level and minimum time deviations for non-transit phases for the second level. Based on this, the semi-ring structure and the backward/forward migration time parameters of coordinated phases are further presented for establishing the constraints. The overall scheme is thoroughly tested and demonstrated in a realistic experimental scenario. Compared with the TSP scheme which takes the coordinated phase as the deadline for adjusting phases, the proposed method can maximize the priority effect by taking full advantage of the migration state of coordinated phases. Moreover, it also reduces the effects to non-transit phases by compensation and traffic-state-based compression mechanisms.

Reliability Assessment of Coordinated Urban Transportation and Power Distribution Systems Considering the Impact of Charging Lots

Owing to spatiotemporal flexibility of electrical vehicles (EVs), EVs will introduce new synergies between the urban traffic system (UTS) and power distribution system (PDS). As a mobile charging load, arranged EV charging can not only provide more flexibility for power system optimization, but also influence the traveling time and other mobility-related characteristics of EVs. However, there are few studies that consider the impact of the coupling facility (such as parking lot with charging facilities) on UTS reliability, as well as the reliability of UTS and PDS (referred to as PTS). Therefore, it is necessary to extend the original research scope to incorporate the traffic system simulation into the collaborative analysis of the coordinated PTS. This paper first develops a new simulation framework for the coordinated UTS and PDS coupled with commercial charging lots (CLs). Then, a new method is illustrated for measuring the reliability of a coordinated UTS and PDS. At last, a novel unified PTS reliability index considering both UTS and PDS reliability indices are presented.

VVS: Fast Similarity Measuring of FoV-Tagged Videos

In this article, we propose a novel method that can measure the similarity of FoV-tagged videos in two dimensions. Recently many researchers have focused on measuring the similarity of FoV-tagged videos. The similarity measurement of FoV-tagged videos plays an important role in various societal applications, including urban road networks, traffic, and geographic information systems. Our preliminary work introduced the Largest Common View Subsequences (LCVS) algorithm for computing the similarity of FoV-tagged videos. However, LCVS requires a high computational cost for calculating common viewable regions between two FoV-tagged videos. To handle this limitation, we propose the largest View Vector Subsequence (VVS) algorithm for reducing the computational cost of FoV-tagged videos. VVS uses the movement distances and the viewable direction distances to support the simplified vector-based similarity measurement. We demonstrate the superiority of our approach by comparing it with the Longest Common Subsequences (LCSS) and our prior work (LCVS). Our experimental results show that VVS outperforms the prior work in terms of the computational cost and enhances the versatility and stability of the similarity measurement.

Modelling and simulation of urban traffic system: present and future

Modelling and simulation of urban traffic system: present and future

Preventive Maintenance Decision Model of Urban Transportation System Equipment Based on Multi-Control Units

This paper studies the fault prediction of equipment and the decision of joint equipment maintenance in urban traffic system based on Internet of Things and big data as the background of multiple control units, and proposes a joint equipment monitoring model for multi-equipment systems composed of intelligent control units. The network method predicts the fault of the equipment and gives the equipment fault prediction process. Combining the multi-equipment system attributes of intelligent control unit, aiming at minimizing the total maintenance cost of control unit system, and taking the reliability of the whole system and the availability of equipment as constraints, a preventive maintenance decision model for joint equipment maintenance is established. Finally, the optimal preventive maintenance interval of the entire system is solved.

Assessment of the state of development of the urban traffic system (on the example of Nur-Sultan)

Assessment of the state of development of the urban traffic system (on the example of Nur-Sultan)

The impact of intelligent transportation points system based on Elo rating on emergence of cooperation at Y intersection

The construction of intelligent transportation system is of great benefit to the efficiency, safety and fairness of urban residents’ travel. This paper focuses on a passing dilemma at Y intersection. An intelligent transportation points system (ITPS) based on Elo rating system is proposed to attempt to solve this dilemma. The drivers in the simulation system are given reinforcement learning ability based on Q-learning algorithm, by evaluating the benefits of each behavior. The conclusions are summarized as follows. For pure selfish drivers group, the application of ITPS has little impact on cooperation. For heterogeneous drivers group, the cooperation probability and passing efficiency of drivers can be improved by the regulation of the ITPS. Meantime, the fairness between drivers could be also maintained. It means that the application of ITPS can achieve the unity of fairness and efficiency. From a long-term perspective, the establishment of the ITPS will be a strong guarantee for the reciprocity of the travelers’ efficiency and fairness. Therefore, this study is conducive to the future construction of more perfect urban traffic intelligent system.

Better understanding the choice of travel mode by urban residents: New insights from the catchment areas of rail transit stations

The primary objective of this paper is to systematically and quantitatively analyze the peculiarities of the mode of travel chosen by residents. More specifically, this study focuses on two major aspects: (1) shedding light on the prominent factors that affect choice of travel mode from an innovative perspective of the catchment areas (CAs) of urban rail transit (URT) stations; and (2) mining and comparing the features and advantages of a diverse range of travel modes. Furthermore, it puts forward some proposals for optimizing the structure of the urban transportation system available to the residents. Using a valuable, screened and discretized, survey dataset of good size (10,385 travel activities of 4,080 individuals in 1,454 households in Nanjing, China), two mixed-logit (ML) models are established. One is based on trip origins/destinations within the CAs of the URT stations. The other is based on residence locations. The modeling results reveal that most residents, except those who own a car and/or driving license, are inclined to choose a slow mode of transport (including walking and cycling). Travelers do not notably err towards walking and bus modes during the peak hours and/or when going to work or school instead of cycling. Residents adjacent to the CAs of URT stations are attracted away from other travel modes and have a tendency to select non-motorized modes to access the URT (metro). The contrastive analysis and discussion results can help to provide urban planners, managers, decision and policy makers with useful suggestions and data support for exploring the various factors (household properties, individual attributes, and trip information) affecting residents’ choice of travel mode and seeking the residents’ travel rules. Moreover, our findings have important implications with respect to improving the structure of the choice of travel modes made available to residents and simultaneously be important in maintaining green, low-carbon, and sustainable development of urban traffic systems.

Optimization of work of urban passenger transport

Recommendations for improving the organization of the logistics system of urban passenger traffic based on the formation of adaptive properties proposed. Definitions of organization and lack of organization of the system, target entropy, orderliness, disorder are considered. The calculation of these indicators allows us to conclude how the company is adapted to the external environment. An important feature of all production systems is the focus of their functioning. If such a system is functioning, it means, first of all, that it solves a finite set of tasks to ensure the adaptability of the urban passenger traffic management system to the flow of passengers and with a certain accuracy the goals of organization and management, of which there is also a finite set. The authors come to a fair conclusion that the lack of organization of functioning is a consequence of the influence of the external environment on the control object, while organization is a quantitative measure of the ability of the system to adapt to the effects of environmental factors. The indicator of organization can be proposed as a criterion that assesses the efficiency of the urban passenger transport system. The worse the internal structures are organized, the less efficiently the control system works and the more mobile and uncertain the external environment, the greater the discrepancy between the goal and the final result.

The multi-level urban rail traffic safety based on fuzzy TOPSIS evaluation research

With the expansion of the scale of the urban rail transit network and the increase of the factors affecting the safety of the operation of the network, the operation risk of urban rail transit is also increasing. For urban rail transit network security problems, according to the statistical analysis of urban rail traffic accident, first constructed oriented network station, line, different levels of urban rail traffic safety evaluation index system, from the three levels of urban rail transit network security influence factors were analysed, and further improving the system of safety evaluation index; Secondly, TOPSIS evaluation method based on triangular fuzzy number is used in this paper to evaluate the safety risk of urban rail transit, which overcomes the disadvantage of subjective factors in AHP and FAHP evaluation methods. Finally, the model is calculated and analysed. This paper provides decision-making basis for the safety management department of urban rail transit, and has certain reference significance for improving the safety management level of urban rail transit.

Changes of traffic network and urban transformation: A case study of Xi’an city, China

Urban traffic system plays a decisive role in structuring urban morphology. Sustainable traffic network can not only promote urban structure optimization, but also can achieve sustainable urban transformation (UT). Xi’an, one of the most important central cities in Western China, is selected as the research area. This research analyzes the change of traffic network in the process of UT by using road network density, road network connectivity and traffic service capability indexes to quantify the development of traffic during different period. The results shows that these three indexes are improved by 72.7%, 58.3% and 33.3% respectively after starting UT. (1) After starting UT, the expansion speed of high road network density area was far than speed before. The medium density area spread to the surrounding counties to form the network. (2) High road connectivity areas expanded rapidly and extended to the north and south, while the areas with low value area had not been effectively developed. (3) High traffic service capability area gradually aggregated, mainly extended to south and central of Xi’an We conclude that urban transformation has a positive effect on changes of urban traffic network, and urban traffic network also can promote sustainable urban transformation.

An efficient multiple access control protocol for directional dense urban traffic surveillance system

Artificial intelligence (AI) methods for traffic video analysis have been widely identified as potential solutions for solving hard problems in intelligent transport systems (ITS). To exploit the advantages of AI, dense cameras to monitor the traffic are required to be deployed along the road and at the intersections. The captured videos of these cameras should be back-hauled to the control center, acting as the inputs of the AI methods. To bear such large data traffic load and to cover long transmission range, directional communication technology can be employed, which concentrate the energy of the wireless signal in a specified direction to provide high data rate and long transmission range (up to hundreds of kilometers). In this paper, the communication time extension problem (CTEP) is identified when directional transmission is applied to the dense urban traffic surveillance system, where the wireless signal propagation time approximates the data transmission time. A link distance division-based time division multiple access (LDD-TDMA) protocol is proposed to address the identified CTEP. Firstly, the directional wireless communication links are classified into categories according to the link distance, where nodes located in the same communication ring belong to the same category. Then a link distance aware (LDA)-based slot allocation algorithm is proposed to assign the time slots to the links. The optimal communication rings’ radius is derived in closed form formula, and the minimum average links’ distance is derived. Simulation results show that LDD-TDMA outperforms TDMA by 13.37% when the ring number is 4.

Influences of stack effect and longitudinal ventilation on the movement of buoyancy-driven contaminants in sloping tunnels

Sloping tunnels widely exist in mountainous regions and urban underground traffic systems. The dynamics of buoyancy-driven contaminants in a naturally ventilated slopping tunnel are generally different from that in a horizontal tunnel. Using the brine-water method and the light attenuation technique, we demonstrate that buoyancy-driven source location and source reduced gravity have significant influence on the steady-state density distribution in the sloping tunnel. The results suggest that the stack effect is an important factor influencing the movement of the buoyancy-driven flow in sloping tunnels. Subsequently, the dynamics of the buoyancy-driven flow in a longitudinally ventilated sloping tunnel are investigated. It is found that, under the combined effects of longitudinal ventilation and stack effect, multiple steady states exist for identical boundary conditions.

Reduction of traffic-related particulate matter by roadside plants: effect of traffic pressure and sampling height

Atmospheric particulate matters (PM) caused by urban traffic system put residents’ health at serious risk. As a method of phytoremediation to mitigate this risk, roadside plants show significant potential to remove PM from the air. However, the relationship between traffic pressure, height, and leaves’ capturing capacity is rarely reported. In this study, two common effective roadside plants (Hedera helix, Taxus baccata) with typical leaf shapes (broad and needle-leaved) were selected to explore the foliage capacity under high, middle and low traffic burden. A green wall covered by H. helix was tested to find out the relationship between heights and the amount of accumulated PM. Although the PM capturing capacity varied between different traffic pressures, needle-leaved species generally accumulated more PM than broad-leaved species. For PM10 capturing, needle-leaved species showed higher capacity under all traffic pressures except under the low traffic pressure. For PM2.5 capturing, needle-leaved species accumulated more PM only under the high traffic pressure. Needle-leaved plants were more sensitive to the change of traffic pressures, its PM capturing capacity changed notably between different traffic pressures because its leaf wax is more susceptible to be corroded. Leaf surface contact angle was slightly affected by the change of traffic pressure for broad-leaved species, but for needle-leaved species, it changed greatly. Leaf surface was the main zone for large PM capturing because the large PM was more likely to be stuck in grooves on the leaf surface, while leaf wax was mainly for fine PM absorption because PM with small sizes could adhere to the surface of the wax crystal. By comparing the amount of captured PM by leaf surface of urban roadside plants under different traffic pressures and height ranges, this study optimizes the benefits of roadside plants as traffic-related PM filter under different traffic conditions.

A Novel Infrared Image Enhancement Based on Correlation Measurement of Visible Image for Urban Traffic Surveillance Systems

Infrared imaging sensors are widely employed in urban traffic systems since they are not affected by lighting conditions. However, due to the limitation of hardware and imaging environment, it is difficult to obtain infrared (IR) images at the desired quality. IR images always lack detailed information, which leads to unsatisfying IR image enhancement results with the conventional method. Compared with the IR images, the visible (VIS) images contain detailed information, which could help to enhance the quality of the corresponding IR images. In this article, we propose an effective method to enhance IR images by applying the multi-sensors image. First, we adopt the edge-preserving filter to decompose the IR and VIS images into illumination and reflectance components according to Retinex theory. Second, each region in the IR and VIS image is classified into the related region and non-related region according to the correlation between IR and VIS images. Finally, an adaptive fuzzy plateau HE (AFPHE) is utilized to enhance the illumination component, and a strategy is employed to enhance the detail of the IR reflectance component with the help of VIS images. Experimental results demonstrate that the proposed method can effectively improve the contrast and enhance the detail of the IR images.

Research on Intelligent Multiple Interchange Induction System of Huadu to Dongguan Highway

Urban expressway is an important part of the urban traffic network, which is also the main artery of urban traffic system. The rationality of interchange has a direct impact on the functions of “rapid patency” and “safety comfort” of urban roads. This paper taking Taicheng multiple interchange as the research object, which from expressway Huadu to Dongguan, focuses on improving traffic efficiency, induction accuracy and safety. This research is carried out from making the lines and mark, making high-precision navigation map, and making guidance system to provide solutions for Taicheng interchange.

A Spatio-Temporal Flow Model of Urban Dockless Shared Bikes Based on Points of Interest Clustering

With the advantages of convenient access and free parking, urban dockless shared bikes are favored by the public. However, the irregular flow of dockless shared bikes poses a challenge for the research of flow pattern. In this paper, the flow characteristics of dockless shared bikes are expounded through the analysis of the time series location data of ofo and mobike shared bikes in Beijing. Based on the analysis, a model called DestiFlow is proposed to describe the spatio-temporal flow of urban dockless shared bikes based on points of interest (POIs) clustering. The results show that the DestiFlow model can find the aggregation areas of dockless shared bikes and describe the structural characteristics of the flow network. Our model can not only predict the demand for dockless shared bikes, but also help to grasp the mobility characteristics of citizens and improve the urban traffic management system.

Engaging Stakeholders in Urban Traffic Restriction Policy Assessment Using System Dynamics: The Case Study of Xi’an City, China

With the purpose of limiting the drastically increasing quantity of travel volumes and the sustainability of urban traffic systems, many cities have implemented urban traffic restriction (UTR) policies. However, insufficient stakeholder involvement in UTR policy assessment often leads to a lack of social and political support, in addition to a lack of acceptability with respect to policy implementation. In this background, participatory system dynamics modeling (PSDM) is presented as a methodology to engage stakeholders in UTR policy assessment. By the proposed methodology, a comprehensive case study of UTR policy in the city of Xi’an was illustrated. Based on the assessment results, the leverage point influencing the performance of the UTR policy was identified and discussed, with different policy scenarios simulated and tested. The simulation results show that developing public transportation while implementing UTR policy was indicated as the most reasonable solution at the present stage, and the annual growth rate of private cars should be monitored in the future. The results confirmed that the PSDM methodology can facilitate the system thinking of stakeholders, which is important to reach consensus-based assessment results and to enhance the social support for UTR policy.

Research on seismic resilience of prestressed precast segmental bridge piers reinforced with high-strength bars through experimental testing and numerical modelling

Precast segmental bridge piers are vigorously pursued, especially in low- and medium- seismicity regions, for their merits in accelerating construction, reducing environmental/traffic disturbances, enhancing quality control, etc. Recently, unbonded tendons are utilized to reduce the residual displacement and to facilitate fast rehabilitation of key bridges in the urban traffic system. To further enhance the resilience, prestressed precast segmentally-erected (PPC) piers were fabricated and tested, reinforced with a hybrid of unbonded tendons and high-strength (H) energy dissipation (ED) bars. In this study: (1) cyclic loading tests for the PPC piers with “H” ED bars were reported, and the seismic resilience was quantitatively evaluated and compared with the PPC piers with normal-strength (L) ED bars; (2) the computationally efficient fiber-based finite element (FE) model is developed for the tested PPC piers. Experimental results demonstrated that the “H” ED bars brought out apparent amelioration, in terms of load-carrying, ductility and self-centering capacities. In consideration of rising seismic resilience, “H” ED bars are recommended to replace currently large-scale adopted “L” ED bars in the PPC pier of vital bridges. Through validation with experimental results, the proposed fiber-based FE model is able to provide satisfactory predictions for seismic responses of the tested PPC piers.

Research on Low Carbon Level Evaluation of Urban Transportation System Based on Grey Comprehensive Evaluation

With the rapid development of social economy, the demand for urban transportation is increasing, and the energy consumption and greenhouse gas emission of urban transportation are also increasing year by year. In this situation, energy saving and emission reduction of transportation industry is imperative. This paper studies the evaluation of the low carbon development level of urban transportation system. Based on the research of domestic and foreign literatures and the characteristics of Qingdao, the urban low-carbon traffic evaluation index system is constructed, including transportation infrastructure, transportation services, resources and environment, and transportation policies and regulations. There are 16 evaluation indicators. The entropy weight method is used to determine the weight value of the evaluation index, and then the gray correlation model is used for evaluation. Taking Qingdao as an example, the empirical analysis shows that in recent years, the low-carbon traffic level in Qingdao is constantly changing. At the same time, the correlation degree of each index is analyzed to find out the crux that hinders the development of low-carbon urban transportation.