Green Connected Automated Transportation and Safety

Table of Contents

1. Frontmatter

2. Modeling and Analysis of the Impact of Charging Electric Charged Vehicles on the Grid Load in the Expressways

   Dazhou Li, Wei Gao

   Abstract

   With the development of the energy grid, the number of electric charging cars will gradually increase on the highway. Highways must not only provide enough natural gas and fuel for vehicles, but also have enough electricity to provide a large number of electric charging cars in the future. When electric charging cars on the highway become the main body of the vehicles, the grid load problem caused by the charging of electric charging cars on the highway will be a problem that must be faced and resolved. The present study is aimed to analyze and model the power load on the highways, combined with electric vehicles penetration scenarios, in order to produce geospatial information for potential energy demand with charging stations in the highway. According to the fluid theory, the efficient and timely prediction of the grid load generated by the charging of electric charging vehicles has been proposed. It will not only help the construction of the grid along the highway, but also contribute to the stability, speed and smoothness of highway traffic. This paper selects Shenda Expressway in China as a realistic research object, and analyzes and models the power load demand of charging stations from 3 aspects: peak-to-valley difference, load balancing and voltage excursion.

3. Research on the Time Interval of Discrete Traffic Flow Model

   Liang Rui, Shan Zheng, An Zeping

   Abstract

   In order to verify the accuracy of the discrete traffic flow model and find out the most suitable statistical method of data for model validation, the discrete traffic flow model proposed by Robertson which was suitable for urban arterial between the intersections was studied. The traffic flow of five roads in Beijing city was investigated by multi-spot photography. The traffic flow data were collected at different time intervals according to 1–6 s and verify the discrete traffic flow model proposed by Robertson at different statistical intervals. Finally, the error of the model in different statistical interval of 1–36 s was obtained. The mean and variance of the error were analyzed and the optimal time interval of the survey data in this model was 1–5 s. This conclusion was verified by T test.

4. An Approach to Analyze Commuters’ Transfer Characteristics on the Public Transportation Network in an Incomplete Data Environment

   Shichao Sun

   Abstract

   This paper analyzed commuters’ transfer characteristics on public transportation networks in an incomplete data environment where only smartcard data could be accessed. A frequent-patterns-mining method was proposed, and a case study was given in Shenzhen, China. Specifically, commuters were firstly identified by using smartcard data based on their bus-riding regularity on workdays. Then, frequent correlations between bus routes/metro lines used in long-term rush hours were measured for each commuter. A two-level minimum threshold framework was proposed to evaluate the correlations, and then determine whether commuting trips containing transfers. The results indicated that non-transfer commuting trips accounted for nearly 72% of the total, among which about 87% were taking buses. Moreover, 14% of identified commuters were having commuting trips through one transfer, where interchanges within the same transportation mode were the majority, such as transfers from bus to bus, and transfers between metro lines. It reflected that the efficiency and convenience of transfers from bus to metro needed to be improved.

5. Understanding Metro-to-Bus Transfers in Nanjing, China Using Smart Card Data

   Miaoyan Zhang, Dongwei Liu, Yanjie Ji, Yang Liu

   Abstract

   Understanding metro-to-bus transfers are important in Chinese cities because metro systems in China have not formed extensive networks and metro riders rely heavily on bus services as a feeder and distributor to rail transit services. Given the wide application of automatic fare collection systems using smart card in Chinese transit systems, smart card data with boarding and alighting information has become a new source of data to understand transfer behaviors. This paper takes Nanjing, China as a case study and examines the possibility of using smart card data to understand specifically metro-to-bus transfer behaviors. Smart card data of a weekday and a weekend is used, with a total of over 6.5 million transaction records. The data analysis focused on identifying metro-to-bus transfers and how metro-to-bus transfer behavior (including transfer duration and time of the day) differ by card type, city region and weekend/weekday status. Results of the analysis show similarities and differences in metro-to-bus transfer behaviors across card holder groups, location of metro stations and between weekdays and weekend days. The transfer duration of the students and adults is shorter on weekdays than weekend days. Besides, the transfer duration in the suburbs is longer than urban areas and exurbs. Most metro-to-bus transfers on weekdays concentrate upon peak hours at 8:00 and 17:00. The reasons of these phenomena are discussed in the corresponding chapters. Limitations of the study and future directions are further discussed.

6. Research and Optimization of Vehicle Braking Efficiency Under Different Working Conditions Based on AMESim

   Yiying Wei, Baoliang Ji, Ziyuan Xiong, Jingqiang Liang, Wei Liu, Zhen Huang

   Abstract

   Brake efficiency is one of the most important factors that significantly affects driving safety. In this paper, a simulation model of the braking system was established by using AMESim. The accuracy of the simulation model was evaluated with the real vehicle tests. Based on the established model, the braking efficiency of the vehicles were analyzed under 15 different working conditions with different adhesion coefficient road surfces at high speed, medium speed and low speed. The optimization of the parameters of the braking system was also proposed and studied. Research results show that the model is suitable for the study and optimization of brake efficiency under different working conditions. It lays a theoretical foundation for the research and optimization of automobile braking performance under the complex working conditions; shortens the development period of automobile brake system. At the same time, the model provides the theoretical support for the smart car adaptive cruise control (ACC) and automatic emergency braking (AEB) research.

7. Effects of the Layout of Exhaust Port on the Performance of Smoke Control for Ultra-Wide Immersed Tube Tunnel

   Ying Li, Shenglin Mu, Xiaoyang Ni, Zhongchen Niu, Kaixuan Tang

   Abstract

   Smoke control is a crucial issue in tunnel fire prevention and control, especially in the ultra-wide tunnels, which is arousing more and more attentions. In this paper, the performance of three different exhaust port setting methods on the fire smoke control in the four-lane tunnel of immersed tube is compared and analyzed based on CFD numerical simulation. In the super wide immersed tunnel, increasing the number of smoke outlets on the transverse side of the tunnel can effectively reduce the thickness of the smoke layer and the maximum temperature of the vault under the top centralized smoke exhaust strategy. The efficiency of smoke exhaust of the outlet along the tunnel obviously decreased with its distance far away from the fire. In the design of smoke prevention and exhaust for super wide section immersed tube tunnel, we can consider reducing the gap between the exhaust fume and increasing the number of horizontal exhaust fume to improve the effect of smoke control in tunnel.

8. Research on Safety Management of Inland River Dangerous Chemicals Transportation System Based on System Dynamics and Principal Component Analysis

   Yu Zhao, Zhiyong Lv

   Abstract

   This paper proposes a new method to study the safety of inland river hazardous chemical transportation under dynamic conditions based on the principles of system dynamics by analyzing the related theories of hazardous chemical transportation and comparing the traditional static hazard assessment methods. The system dynamics model of the inland river hazardous chemicals transportation system is constructed in this paper. According to Vensim_PLE, relevant data are obtained by changing the growth rate of the safety input of various factors. Using the principal component analysis (PSC) analysis data to verify the accuracy of the model and study the impact of various factors on the safety of the transportation system. The result shows that human factors and management factors have a greater influence on the safety of the transportation system. It is important to change the input indicators of human factors and management factors to improve safety.

9. Mechanical Properties of Concrete Under the Alternate Carbonation and Freezing–Thawing Actions

   Jin Ran, Qi Feng, Jinxi Zhang, Lin Wang, Honglin Cao

   Abstract

   Three concrete mixes with different water-to-binder ratios and dosages of cement replacement materials (fly ash and slag powder) were exposed to alternate carbonation and freezing–thawing actions. The compressive strength, dynamic elastic modulus and mass of all specimens were measured and analyzed, also compared to the results obtained from the carbonation-only and freezing–thawing-only cases. Test data show that the relative compressive strength, the relative dynamic elastic modulus and the mass of concrete specimens exposed to carbonation-only cases increase with the carbonation time due to sufficient carbonation reaction, whereas they decrease with the corresponding testing time whenever they are exposed to freezing–thawing-only cases or alternate regimes. Additionally, under the same freezing–thawing numbers, the concrete specimens exposed to alternate regimes have slightly higher relative compressive strength, lower relative dynamic elastic modulus and larger mass loss than that exposed to freezing–thawing-only cases. Based on the obtained dynamic elastic modulus from the above different environmental cases, a damage mechanics fitting model of concrete considering alternate carbonation and freezing–thawing actions were established with high reliability.

10. Research on the Top-Level Design of Urban Road Intelligent Promotion

    Jin-dong Zhou

    Abstract

    With the rapid development of the city, urban traffic congestion has become one of the main social problems. The development of urban intelligent transportation is an important solution. As an important carrier of intelligent transportation, urban road has gradually become the focus of urban development. By studying the development process of urban road intelligence, summarizing the development stages and achievements at home and abroad, combining with the latest Internet of things, cloud computing, big data, mobile Internet and other technologies, this paper puts forward the core development concept and overall framework of urban road intelligence promotion, and takes the middle high tech road of Zhangjiang Science City in Shanghai as an example to design the application scheme.

11. Predicting Red Light Running Violation Using Machine Learning Classifiers

    Muhammad Zahid, Arshad Jamal, Yangzhou Chen, Tufail Ahmed, Muhammad Ijaz

    Abstract

    Red light Running (RLR) violation remains as an important road safety concern at urban intersections. Existing method have mostly used statistical regression-based methods to explore factors contributing to RLR. However, it is well-known that statistical methods are based on predefined associations among variables and are unable to capture latent heterogeneity. This study aims to classify and predict RLR using spatial analysis and machine learning (ML) methods. Georeferenced RLR violation data for the year 2016 was collected for the city of Luzhou, China. To identify violation hotpots, frequency-based clustering was carried out using collect event tool in ArcMap geographic information system (GIS). Prior to RLR prediction via ML, data imbalance problem was addressed using a random over-sampling technique. Two widely used ML algorithms, i.e., Random Forest (RF) and Gradient Boosted Decision Tree (GBDT), were then used for prediction and classification of RLR. The performance of these models was assessed with accuracy and Cohen's kappa. The results showed that GBDT had an overall accuracy of 96% outperformed the RF.

12. Bi-Objective Subway Timetable Optimization Considering Changing Train Quality Based on Passenger Flow Data

    Hanlei Wang, Peng Wu, Yuan Yao, Xingxuan Zhuo

    Abstract

    As an effective transport mode, rail systems have been developing rapidly in recent years. A reasonable timetable not only enables passengers to have a better travel experience, but also saves the operating cost of subway companies. Therefore, the timetable design is the key to the reliability of subway services. Based on actual passenger flow, this paper develops a new bi-objective integer programming model with the objectives of minimizing the total passenger waiting time and the net energy consumption of trains simultaneously. To effectively solve the proposed model, a problem-specific non-dominated sorting genetic algorithm is proposed. A case study based on Metro Line 1 of Fuzhou, China, illustrates the effectiveness and efficiency of the proposed approach.

13. Wind Tunnel Tests on Aerodynamic Noise from the Head Car of a High-speed Train

    Hai Deng, Yigang Wang, Qiliang Li, Zhe Shen, Yang Gao, Jin Lisheng

    Abstract

    Characteristics of aerodynamic noise is always difficult to extract by both experimental and numerical methods. Based on the aero-acoustic wind tunnel test results of a 1:8 scale high-speed trains model with three cars, the properties of the aerodynamic noise sources of the head car were analyzed. In view of the fact that dipole source is the main aerodynamic noise source of the high-speed train, the acoustic similarity relationship between the different models was deduced. Subsequently, the aerodynamic noise properties of the 1:1 scale model (approximate full-scale train) were analyzed. The results show that the main noise sources of the 1:1 scale model are the bogie regions and the noise energy of 80 Hz–4 kHz is dominant at the train speed of 250 km/h. The noise is the strongest at the frequency of 160–400 Hz, and the noise of the nose tip and the obstacles is the same order as that of the bogie area after 2.5 kHz. The acoustic similarities between the different models are related to the third power of the speed, and the first power of the model length, the propagation distance and the frequency. The noise difference between the different models is related to scale size and frequency. The frequency at full scale has an exponential relationship with the scale model’s frequency, not following a liner relationship with the scale.

14. Invulnerability Simulation of Urban Agglomeration Traffic Network Cascading Failure Under Random Attack Strategy

    Chengbing Li, Zhicheng Yang, Zhenyu Liu

    Abstract

    Aiming at the cascading failure problem in urban agglomeration traffic network, this paper proposed a new cascading failure model. In this model, we divided the node states into normal, pause, and failure with the judgment criterion of the degree of node overload. For the pause node we adopted the flow distribution rule of residual capacity priority, and for the failure node, the flow distribution was based on the node distance and degree of connectivity. Meanwhile, this paper also considered the enduring ability between nodes or edges in the load transfer process. We studied the effects of overload capacity parameter which means the node redundancy capacity, passenger flow adjustment which means the initial network load, and the impact of different attack strategies on urban agglomeration traffic network invulnerability with the simulation of actual passenger flow in Hu-Bao-E urban agglomeration. The results show that the overload capacity parameter has a threshold of 1.2 with the node attacks, so the invulnerability would not be improved when we increase the value of overload capacity parameter. The influence of passenger flow adjustment parameter on network invulnerability shows different characteristics under different attack patterns. Compared with the attack edge, the attack node has a more significant impact on traffic network invulnerability, because node bears large passenger flow, and it will easily be cascading failure when it is attacked. And in the attack process, it shows the cliff-like decline phenomenon of correction relative scale of maximum connected subgraph, and the urban agglomeration traffic network has an extremely strong scale-free characteristic.

15. Impact of Intelligent Networking on Vehicles Exiting at Urban Intersections

    Jun Liu, Shu-Bin Li

    Abstract

    Intelligent network connection was expected to completely break the existing rules and orders of transportation system. The theoretical peak speed of 5G wireless bandwidth could reach more than 10 Gb per second, which enables cars to exchange information such as location, speed, and destination. It would provide a technical basis for real-time information sharing among vehicles. Based on the formal study of Neural Networks, we added Gaussian noise in the RBM top-level connecting regression, constructing a CDSHybird model that could predict traffic flow in the urban intersections. The results showed that the model proposed in this paper could reflect the movement of vehicles passing through urban intersections in various situations. Further development of interconnection would probably realize the control of traffic flow without a traffic light, which could maximize the efficiency of traffic.

16. Safety Evaluation of Expressway Linear Operation Based on Design Consistency

    Ke Chen, Jian-Feng Jiang, Jia-Jia Tian, Yun-You Liu, Yanli Ma

    Abstract

    In order to solve the problem of coordination between speed and alignment design of expressway in China, and improve the safety of expressway operation. On the basis of determining the operation safety evaluation index, combined with the existing domestic traffic safety evaluation research data, referring to the American interactive highway safety design model (IHSDM), this paper build an improved highway alignment operation safety evaluation model considering design consistency. A case study is carried out to verify the effectiveness of the model. The results show that the accuracy of the model is 83.33%, which can effectively evaluate the operation safety of highway alignment design, and the research results are positive. It is of great theoretical and practical significance to guide the safety evaluation of highway alignment operation in China.

17. Forecast Model of Comprehensive Transport Freight Index Considering Macro Economy in China

    Yanli Ma, Jieyu Zhu, Yining Lou

    Abstract

    To better construct the coordinated development of the comprehensive transportation system, the prediction model of comprehensive freight index in China was studied. Basic indicators of production and supply, benefits and macroeconomic were selected. Cluster analysis was used to divide the indicators into 13 leading indicators and 13 synchronous indicators. Factor analysis was used to analyze the importance of each leading indicator. The characteristic quantities of freight index were determined and the Granger causality test was conducted between the four indexes and the five characteristic quantities respectively. The relationship model between each freight index and characteristic quantity was constructed, and the validity of the model was verified. Results show that the freight indexes are volatile. There is a stable relationship between characteristic quantity and freight index. The error of forecast and actual value of is within 10%, verifying the validity of the model. The results can provide theoretical support for forecasting the development trends of freight transport among various transport modes. The comprehensive transport will be improved to provide a decision-making basis for the national macro-department to make policies.

18. An Optimization Model of Passenger Transportation Structure Based on Land Use and Energy Consumption

    Fenghe Yu, Yining Lou, Lifei Han, Jieyu Zhu

    Abstract

    Passenger transportation structure (PTS) features a huge effect on the proficiency of the territorial comprehensive traffic framework. Therefore, one of the important means to improve its efficiency is to rationalize and optimize the passenger transportation structure. From a static point of view, this paper puts forward user optimum thought to meet the demand of regional passenger optimal thought and constructed an optimization model of the passenger transportation structure on the basis of land and energy consumption. Through analysis of the passenger transportation systems of Harbin, Daqing, and Yichun in China, a model was designed by simulation and the proportion of the traveler transportation organization were determined. The method of fuzzy comprehensive was used to assess the traveler transportation arrangement, which is based on optimization model and real-world data. The effectiveness of the optimization model was demonstrated by analysis of the evaluation results. The displayed method and estimation results can help transportation organizers and policy-makers in deciding future traveler transportation foundation speculation needs.