Effects of real-time traffic information systems on traffic performance under different network structures

The effects of real-time traffic information system(RTTIS)on traffic performance under parallel,grid and ring networks were investigated.The simulation results show that the effects of the proportion of RTTIS usage depend on the road network structures.For traffic on a parallel network,the performance of groups with and without RTTIS level is improved when the proportion of vehicles using RTTIS is greater than 0 and less than 30%,and a proportion of RTTIS usage higher than 90%would actually deteriorate the performance.For both grid and ring networks,a higher proportion of RTTIS usage always improves the performance of groups with and without RTTIS.For all three network structures,vehicles without RTTIS benefit from some proportion of RTTIS usage in a system.

Multi-objective evolutionary approach for UAV cruise route planning to collect traffic information

Unmanned aerial vehicle(UAV)was introduced as a novel traffic device to collect road traffic information and its cruise route planning problem was considered.Firstly,a multi-objective optimization model was proposed aiming at minimizing the total cruise distance and the number of UAVs used,which used UAV maximum cruise distance,the number of UAVs available and time window of each monitored target as constraints.Then,a novel multi-objective evolutionary algorithm was proposed.Next,a case study with three time window scenarios was implemented.The results show that both the total cruise distance and the number of UAVs used continue to increase with the time window constraint becoming narrower.Compared with the initial optimal solutions,the optimal total cruise distance and the number of UAVs used fall by an average of 30.93% and 31.74%,respectively.Finally,some concerns using UAV to collect road traffic information were discussed.

CHRT:Clustering-Based Hybrid Re-Routing System for Traffic Congestion Avoidance

Re-routing system has become an important technology to improve traffic efficiency.The traditional re-routing schemes do not consider the dynamic characteristics of urban traffic,making the planned routes unable to cope with the changing traf-fic conditions.Based on real-time traffic information,it is challenging to dynamically re-route connected vehicles to alleviate traffic congestion.Moreover,how to obtain global traffic information while reducing communication costs and improving travel efficiency poses a challenge to the re-routing system.To deal with these challenges,this paper proposes CHRT,a clustering-based hybrid re-routing system for traffic congestion avoidance.CHRT develops a multi-layer hybrid architecture.The central server accesses the global view of traffic,and the distributed part is composed of vehicles divided into clusters to reduce latency and communication overhead.Then,a clustering-based priority mechanism is proposed,which sets priorities for clusters based on realtime traffic information to avoid secondary congestion.Furthermore,to plan the optimal routes for vehicles while alleviating global traffic congestion,this paper presents a multi-metric re-routing algorithm.Through extensive simulations based on the SUMO traffic simulator,CHRT reduces vehicle traveling time,fuel consumption,and CO2 emissions compared to other systems.In addition,CHRT globally alleviates traffic congestion and improves traffic efficiency.

A new measure for evaluating spatially related properties of traffic information credibility

With the wide applications of sensor network technology in traffic information acquisition systems,a new measure will be quite necessary to evaluate spatially related properties of traffic information credibility.The heterogeneity of spatial distribution of information credibility from sensor networks is analyzed and a new measure,information credibility function(ICF),is proposed to describe this heterogeneity.Three possible functional forms of sensor ICF and their corresponding expressions are presented.Then,two feasible operations of spatial superposition of sensor ICFs are discussed.Finally,a numerical example is introduced to show the calibration method of sensor ICF and obtain the spatially related properties of expressway in Beijing.The results show that the sensor ICF of expressway in Beijing possesses a negative exponent property.The traffic information is more abundant at or near the locations of sensor,while with the distance away from the sensor increasing,the traffic information credibility will be declined by an exponential trend.The new measure provides theoretical bases for the optimal locations of traffic sensor networks and the mechanism research of spatial distribution of traffic information credibility.

Real-time traffic information extraction based on compressed video with interframe motion vector

Extraction of traffic information from image or video sequence is a hot research topic in intelligenttransportation system and computer vision. A real-time traffic information extraction method based on com-pressed video with interframe motion vectors for speed, density and flow detection, has been proposed for ex-traction of traffic information under fixed camera setting and well-defined environment. The motion vectors arefirst separated from the compressed video streams, and then filtered to eliminate incorrect and noisy vectors u-sing the well-defined environmental knowledge. By applying the projective transform and using the filtered mo-tion vectors, speed can be calculated from motion vector statistics, density can be estimated using the motionvector occupancy, and flow can be detected using the combination of speed and density. The embodiment of aprototype system for sky camera traffic monitoring using the MPEG video has been implemented, and experi-mental results proved the effectiveness of the method proposed.

Research on Data Tampering Prevention Method for ATC Network Based on Zero Trust

The traditional air traffic control information sharing data has weak security characteristics of personal privacy data and poor effect,which is easy to leads to the problem that the data is usurped.Starting from the application of the ATC(automatic train control)network,this paper focuses on the zero trust and zero trust access strategy and the tamper-proof method of information-sharing network data.Through the improvement of ATC’s zero trust physical layer authentication and network data distributed feature differentiation calculation,this paper reconstructs the personal privacy scope authentication structure and designs a tamper-proof method of ATC’s information sharing on the Internet.From the single management authority to the unified management of data units,the systematic algorithm improvement of shared network data tamper prevention method is realized,and RDTP(Reliable Data Transfer Protocol)is selected in the network data of information sharing resources to realize the effectiveness of tamper prevention of air traffic control data during transmission.The results show that this method can reasonably avoid the tampering of information sharing on the Internet,maintain the security factors of air traffic control information sharing on the Internet,and the Central Processing Unit(CPU)utilization rate is only 4.64%,which effectively increases the performance of air traffic control data comprehensive security protection system.

Estimation of the Impact of Traveler Information Apps on Urban Air Quality Improvement

With the rapid growth of vehicle population and vehicle miles traveled, automobile emission has become a severe issue in the metropolitan cities of China. There are policies that concentrate on the management of emission sources. However, improving the operation of the transportation system through apps on mobile devices, especially navigation apps, may have a unique role in promoting urban air quality. Real-time traveler information can not only help travelers avoid traffic congestion, hut also advise them to adjust their departure time, mode, or route, or even to cancel trips. Will such changes in personal travel patterns have a significant impact in decreasing emissions？ If so, to what extent will they impact urban air quality？ The aim of this study is to determine how urban traffic emission is affected by the use of navigation apps. With this work, we attempt to answer the question of whether the real-time traffic information provided by navigation apps can help to improve urban air quality. Some of these findings may provide references for the formulation of urban traffic and environmental policies.

Epidemic-Like Proximity-Based Traffic Offloading

Cellular networks are overloaded due to the mobile traffic surge,and mobile social networks(MSNets) can be leveraged for traffic offloading.In this paper,we study the issue of choosing seed users for maximizing the mobile traffic offloaded from cellular networks.We introduce a gossip-style social cascade(GSC) model to model the epidemic-like information diffusion process in MSNets.For static-case and mobile-case networks,we establish an equivalent view and a temporal mapping of the information diffusion process,respectively.We further prove the submodularity in the information diffusion and propose a greedy algorithm to choose the seed users for traffic offloading,yielding a sub-optimal solution to the NP-hard traffic offloading maximization(TOM) problem.Experiments are carried out to study the offloading performance,illustrating that the greedy algorithm significantly outperforms the heuristic and random algorithms,and user mobility can help further reduce cellular load.

城市交通信息化发展状况评估研究

城市交通的信息化是解决城市交通问题的有效途径,也是必然趋势.介绍了交通信息化的内涵和要素,重点讨论了城市交通信息化的实现平台——城市交通信息系统,构建了评价城市交通信息化发展状况的指标体系,最后基于系统可靠性理论中的序贯思想,以某城市为例讨论了城市交通信息状况的评估算法.

微服务框架下的交通信息化架构

文中在讨论了交通信息化的意义以及交通信息系统的重要性的情况下,分析了目前交通信息系统存在的问题,针对现有的问题,提出了基于微服务的交通信息化框架,论证了交通信息系统基于微服务实现的可行性。通过构建了交通信息系统微服务化的架构,文中从系统基础架构和交通信息系统业务两个层面上提出了解决思路:系统的权限管理,微服务的治理方案,微服务集群的容器化部署,以及交通信息业务中的信息采集、信息处理、信息发布三大业务模块的微服务化方案。

Urban Traffic Information Service Application Grid

Traffic information processing is very complicated because of dynamic, cooperative and distributed features. This paper describes the prototype system version 2.0 of Urban Traffic Information Service Application Grid (UTISAG), which is based on the previous version. In this version, a new architecture and more enhanced services are introduced, The. remarkable characteristic of the new system is providing dynamic information services for travelers by grid technology. Therefore, the key research includes integrating large multi-source traffic data, forecasting route status, simulating regional traffic flow parallelly, and implementing optimum dynamic travel scheme based on massive GPS data.

Method of Generating Strategic Guidance Information for Driving Evacuation Flows to Approach Safety-Based System Optimal Dynamic Flows: Case Study of a Large Stadium

In previous evacuation flow planning, a system optimal dynamic traffic assignment(SODTA) did not consider the exogenous costs caused by potential traffic accidents. A traffic accident,which might occur as a result of traffic congestion, will impact an evacuation process because of accidentrelated delays experienced by the downstream vehicles. This paper establishes a safety-based SO-DTA linear programming model in which the generalized system cost incorporates both the travel time and the accident-related delay. The goal is to minimize the generalized system cost under the cell transmission setup. Furthermore, the authors provide strategic guidance information that considers both the objective of the decision maker and the route choice behavior of the evacuees. Mathematically,the authors propose an unconstrained non-linear programming model aimed at minimizing the gap between the safety-based flows and the stochastic real-world evacuation flows, to provide strategic travel time information to be published on variable message signs(VMS). In the case study, the authors found that the safety-based SO-DTA model can reduce congestion and improve the evacuation efficiency; the stochastic real-world evacuation flows, guided by strategic information, can approach the safety-based flows.

智能交通发展的有关问题的探讨 在“2005北京·中国交通论坛”上的发言

首先分析了智能交通应产生的效益,并以ITS收费系统为例分析了日本实施自动收费后,所产生的效益以及日本在发展VICS系统所取得的效果.而在欧洲、美国ITS效果就不怎么成功,这是与它们运作方式和社会习惯有关.其次,谈到信息化引起交通管理的变化,运输工具的信息都是单向作用的,作为运营商,按照线网和能力要求考虑问题,制定了运行时间表,乘客和货主就得按网上安排它们的出行和运送.我们已进入ITS发展时代,就要根据用户需求安排网络,以及对整个管理的影响,这说明现代技术带来的变化.第三,谈到建设智能交通如何节省投资问题,举出了北京二环路和三环路可变交通信息板是全屏显示,投资较大,而上海有一个节省投资的理念,在信息板上,不应该有与交通无关的信息,而且要让人一眼就能把交通信息看出来,这说明观念不一样,就确定了智能交通技术运用的不同、投资也不同.第四,谈到交通与社会的关系、制度和社会形态对技术应用也有影响,如中国一个综合交通管理部门,我们就没有必要再使用综合信息平台这项技术了.最后,谈到对智能交通发展过程能否可用数学描述和找出合适的模型,他认为由于交通与社会的关系复杂,如何才能找出实用的数学描述与模型现在尚未解决,请大家继续研究.

Real-time urban traffic information estimation with a limited number of surveillance cameras

Constant traffic congestion consumes enormous amounts of energy and causes vastly increased journey times. Therefore, real-time traffic information is of great importance to the public because such information is invaluable to more efficient traffic control and travel planning. To obtain such information in metropolises like Shanghai, however, is very challenging due to the extraordinarily large scale and com- plexity of the underlying road network. In this paper, we pro- pose a novel traffic estimation scheme utilizing surveillance cameras pervasively deployed in cities. With only a limited number of roads with cameras, we adopt a measurement- based traffic matrix （TM） estimation method to infer the traf- fic conditions on those roads with no cameras. Extensively trace-driven simulations as well as field study results show that our scheme can achieve high accuracy with a very limited number of measurements. The accuracy of our measurement- based algorithm outperforms the traditional speed-based and model-based approaches by up to 50%.

浅谈筑养路机械设备管理信息化

分析了现阶段新疆公路系统施行筑养路机械设备管理的制度及方法。结合新疆公路系统的实际情况,从增强筑养路机械设备管理水平,提高设备利用率,加快设备更新等方面,提出了如何抓住机遇,适应公路建设的快速发展,和进一步加快、完善筑养路机械设备管理信息化建设的建议。

主枢纽城市公路交通信息化建设构想

主枢纽城市交通信息化建设是实现交通现代化、网络化、智能化的具体体现。

Navigation Accuracy Category-Position Models and Estimate Position Uncertainty Calculations for TIS-B System

Navigation accuracy category-position （NACp） is an important parameter for system accuracy of traffic information service-broadcast （TIS-B）, which is determined by estimate position uncertainty （EPU）. Centered about the problems that the exist ing EPU calculation based on noise measurement is low in accuracy and unfit for describing uncorrected biases in target reports, this article analyses the traditional NACp model, and uses the least square estimation （LSE） in EPU calculation. Furthermore, it proposes an extended NACp model, which considers both noise and biases and acquires EPU estimation with the help of approximate multiplex Taylor expression. Analysis and simulation show that the proposed method not only leads to significant improvement of the accuracy of EPU calculation, but is fit for EPU calculation with tracking biases in TIS-B system as well. As such it can find application in practice to depict different kinds of error models in TIS-B system.

A distributed pavement monitoring system based on Internet of Things

Pavement is an important part of transportation infrastructure.In order to maintain pavement before the damage and improve the service quality,it is necessary to develop an intelligent and durable pavement information monitoring system.However,the pavement dynamic response monitoring is highly costly,easily obsolete and statistically redundant.The emergence of the Internet of Things(IoT)technology promises to change that.In this paper,an architecture of a distributed road IoT monitoring system is proposed,which has an acquisition layer,a preprocessing layer,a processing layer,an interaction layer,an energy layer and a network layer.Then,a prototype wireless pavement vibration monitoring system based on the IoT is developed,which consists of a number of wireless sensing nodes,a gateway,a remote server and a browser.Finally,data preprocessing,wireless communication,time synchronization,data processing and visualization,which represent the key to an effective system,are tested and discussed.The prototype wireless pavement vibration monitoring system provides a viable scheme for upgrading the IoT system and its application in the road infrastructures.In the future,any smart road will have an IoT wireless monitoring system to monitor the traffic,environment,and pavement information,which help enable traffic guidance,signal control,danger warning,scientific maintenance decision-making.

Deriving average delay of traffic flow around intersections from vehicle trajectory data

Advances of positioning and wireless commu- nication technologies make it possible to collect a large number of trajectory data of moving vehicles in a fast and convenient fashion. The data can be applied to various fields such as traffic study. In derive average delay of traffic and verify the results with this paper, we attempt to flow arotmd intersections changes of time. The intersection zone is delineated first. Positioning points geographically located within this zone are selected, and then outliers are removed. Turn trips are extracted from selected trajectory data. Each trip, physically consisting of time-series positioning points, is identified with entry road segment and turning direction, i.e. target road segment. Turn trips are grouped into different categories according to their time attributes. Then, delay of each trip during a turn is calculated with its recorded speed. Delays of all trips in the same period of time are plotted to observe the change pattern of traffic conditions. Compared to conven- tional approaches, the proposed method can be applied to those intersections without fixed data collection devices such as loop detectors since a large number of trajectory data can always provide a more complete spatio-temporal picture of a road network. With respect to data availability, taxi trajectory data and an intersection in Shanghai are employed to test the proposed methodology. Results demonstrate its applicability.

Hierarchical predictive energy management strategy for fuel cell buses entering bus stops scenario

This paper aims to answer how to use traffic information to design energy management strategies for fuel cell buses in a networked environment.For the buses entering the bus stops scenario,this paper proposes a hierarchical energy management strategy for fuel cell buses,which considers the traffic information near the bus stops.In the upper-level trajectory planning stage,the optimal SOC trajectory under various historical traffic conditions is solved through dynamic planning.The traffic information and the best SOC trajectory are mapped through BiLSTM,which can achieve fast,real-time long-term SOC reference.In the lower-level real-time predictive energy management strategy,the optimal SOC is used as the state reference to guide the predictive energy management of fuel cell buses when entering the bus stops.Simulation results show that compared with the strategy without SOC trajectory reference,the life cost of the proposed strategy is reduced by 13.8%,and the total cost is reduced by 3.61%.The SOC of the proposed strategy is closer to the DP optimal solution.