2017 No. 6

2017, 35(6) doi: 10.3963/j.issn.1674-4861.2017.06.016
Abstract(315) PDF(0)
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Overview
Transportation Information and Safety in Intelligent and Connected Environment: A Review for the 4th International Conference on Transportation Information and Safety (ICTIS 2017)
XUE Jie, WANG Xianglong, CHEN Chen, WU Haoran, WU Chaozhong
2017, 35(6): 1-9. doi: 10.3963/j.issn.1674-4861.2017.06.001
Abstract(658) PDF(2)
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Transport information is the basis for transportation development.Meanwhile,transport at..on safety is one of the important purposes for transportation studies.It has attracted attention from academia within the intelligent and connected transportation environment.The 4th International Conference on Transportation Information and Safety (ICTIS 2017) is committed to promoting the developments of transport information and safety.Hot issues on the core contents are discussed,including diversified application of maritime information,maritime accident analysis and ship collision avoidance,information interaction between road and infrastructure,and optimization of public transportation.The latest research results are elaborated as well.Issues discussed at the conference are summarized;the trends and existing problems of traffic safety are discussed.Further research directions of transport at:on information and safety are also mentioned during the conference,and the direction includes safety risk and prevention of new energy ship,dynamic forecasting of multi-class and multi-mode of traffic flows,developments and applications of Unmanned Surface Vessel,road and traffic safety information modeling.
Transportation Safety
State-observer Based Identification of Traffic Accidents on Urban Freeways
GUO Yuqi, CHEN Yangzhou
2017, 35(6): 10-18. doi: 10.3963/j.issn.1674-4861.2017.06.002
Abstract(574) PDF(0)
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Traffic accidents are with a higher occurrence rate on urban freeways.An estimated algorithm of state observer based on a macroscopic traffic flow model is proposed with a purpose to identify traffic accidents accurately and timely.Data of traffic flow before and after accidents which simulated by Paramics software are recorded and analyzed by using the Cell Transmission Model (CTM) theory.Distribution characteristics of traffic densities around accident segments are studied.An estimation model is designed based on the traffic flow model.Therefore,this estimation model can be implemented to identify traffic accidents by checking variation feature of estimated densities and distribution characteristics of traffic.Finally,a case study on Jingtong freeway is conduct,the average value of Mean Percentage Error (MPE) of the experimental section is 11.56%,the accuracy of the model reaches 88.44%.The results show that the estimation model proposed in this study can be implemented for traffic accidents identification,and provide effective references in practice.
An Early Warning Method of Curve Roads in Mountain Areas
XU Duo, FANG Shou'en, CHEN Yuren
2017, 35(6): 19-24,53. doi: 10.3963/j.issn.1674-4861.2017.06.003
Abstract(615) PDF(5)
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Accident rate of curve roads in mountain areas is often higher than which in general sections.Due to sight distance and some reasons,drivers cannot easily identify risks of curve roads.A method for early warning of curve roads is developed.A simulation is set up based on driving modes of front vehicles and road conditions in mountain areas,in order to provide valid information and complete chain transfer of information.The relations between velocity,acceleration,and curves are analyzed.Frequency diagrams and distribution of correlation coefficients are computed.The results show that four variables taken into this model as independent variables is feasible.An early warning model is developed by using the historical data and Elman recurrent neural network.Compared with two binary logistic regression and BP neural network,the accuracy rate of this model is 85.59%.The validity of the model is verified.
A Selection Model of Traffic Safety Facility in School Zones
LI Jiahui, ZHAO Xiaohua, WAN Yuhan
2017, 35(6): 25-31. doi: 10.3963/j.issn.1674-4861.2017.06.004
Abstract(563) PDF(1)
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Traffic safety facility plays an important role in improving traffic safety in school districts.However there are two problems when deploying traffic safety facilities in engineering practice:① whether installation of traffic safety facilities is effective;② whether a new facility is necessary to increase the effectiveness of existing facilities.A selection model is developed in order to solve those problems.Two representative school districts in Beijing are selected as a case study for driving simulation.Average speed,relative speed difference,and standard deviation of acceleration are selected as quantificational indicators to evaluate performances of traffic safety facilities in those two school districts.Flashing Beacon is selected as the focus to explain the selection model of traffic safety facility.The results show that the proposed model can provide a generic framework to assess different traffic safety facilities combinations performance in school districts.
A Simulation Analysis of Pavement Skid Resistance Against Driving Safety on Curve Roads
WANG Weifeng
2017, 35(6): 32-37. doi: 10.3963/j.issn.1674-4861.2017.06.005
Abstract(469) PDF(0)
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In order to study impacts of pavement skid resistance against driving safety on curve roads,especially in a situation of braking,a vehicle-tire-road model by integrating parameters of analytical UA tire,vehicle body,and road pavement skid resistance is developed based on the ADAMS simulation platform.Kinematic parameters of vehicle in the model are derived on curve roads under different conditions of slippery pavement.Relationships between pavement skid resistance and kinematic parameters which indicating driving safety are studied.Simulation results show that varied pavement skid resistance can lead changes of kinematic parameters,which is the key factor causing potential traffic accidents.Lower skid resistance leads to rollover of vehicles,and slippery disparity in two sides of the road contacted with tires raises the risk of getting vehicles out of roads.This study can provide theoretical references for making measures to guarantee driving safety on curve roads.
A Gray Evaluation Method of Flight Safety Risk Based on Comprehensive Integration Weight Method
GU Qianqian, DING Songbin
2017, 35(6): 38-45. doi: 10.3963/j.issn.1674-4861.2017.06.006
Abstract(619) PDF(0)
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In order to improve evaluation accuracy of flight safety risk,grey system theory and comprehensive integration weight method are combined to develop a quantitative evaluation method considering uncertainties of factors affecting safety risk of flights.An index system is established from four aspects of crew,equipment,environment,and management.The weight of each index is determined by the comprehensive integrated weight method based on the principle of minimum entropy.A model is developed based on gray system theory,which is used to evaluate flight safety risk,and define the main indices which affect safety of flights.Rationality and feasibility,and effectiveness of this method are validated from a case study.The results show that the method can solve the problem of uncertainties in evaluation processes to the maximum extent.
Transportation Information Engineering and Control
A Quantitative Method for Traffic Capacity of Channels Based on Clustering of Ship Types
LIU Jingxian, LIU Cong, ZHAO Zhen, ZHANG Mingyang, LIU Zhao
2017, 35(6): 46-53. doi: 10.3963/j.issn.1674-4861.2017.06.007
Abstract(531) PDF(0)
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In order to compute traffic capacity of hybrid channels which changes from one-way to two way navigation,a quantitative model is developed based on clustering of ship types.According to the regulations of ship navigation in seaports,different ship types are classified.Characteristics of ship types and their probability distribution are determined by using a cluster algorithm.Compared with traditional methods,this method is more accurate to quantify traffic capacity of channels by assigning weights of different types of ships according to their occupied spaces.Moreover,the influences of different navigation modes on traffic capacity are also considered,which makes the model more accurate.The Dagusha Shipping Channel in Tianjin Port is taken as a case study to verify the proposed model.Current capacity of this channel is around 1 905 ships per month,while computed capacity is 2 350 ships per month.Moreover,while using the model for hybrid channels,the result is 4 455 ships per month,which is significantly larger than actual capacity of the channel.The results show that the method based on clustering of ship types can reflect the actual situation of the channel.
An Analysis on Acceptance of Advanced Driver Assistance Systems and Influencing Factors
LYU Nengchao, QIN Ling, LUO Yi
2017, 35(6): 54-59. doi: 10.3963/j.issn.1674-4861.2017.06.008
Abstract(604) PDF(1)
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Studies on drivers' acceptance of Advanced Driver Assistance Systems (ADAS) and its influencing factors is beneficial to promote and improve it.A total of 46 subjects are recruited in a case study to drive vehicles with and without ADAS,on 105 km typical roads in Wuhan,then complete a questionnaire of basic information and acceptance of ADAS.Based on a technology acceptance model (TAM),drivers' acceptance of ADAS is analyzed.A variance analysis method is used to study influencing factors.The results show that the average acceptance of ADAS about 43 drivers is 80.9 % (SD =0.191).Factors as gender,age,and driving experience of drivers have no significant influence on the acceptance of ADAS.However,different ADAS has different acceptance:FCW system is higher accepted,while LDW system is lower accepted.Different types of roads also significantly affect the acceptance,which is lowest on the city roads.
A Study on Numerical Simulation of Hydrogen Leakage in Cabin of Fuel Cell Ship
LI Feng, YUAN Yupeng, YAN Xinping, LIU Hanlin
2017, 35(6): 60-66. doi: 10.3963/j.issn.1674-4861.2017.06.009
Abstract(653) PDF(2)
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A fuel cell ship carries a large amount of hydrogen as fuel,which brings threat to safety of the ship owing to characteristics of hydrogen as easy to leak or explode.A 3D geometric model of fuel cell cabin from a target ship is established to develop a scenario of hydrogen leakage happening in the cabin.On the basis of this model,the leakage rate of hydrogen from pipeline is computed by defining an ideal gas model and leakage parameters.Afterwards,transient leakage and diffusion processes of hydrogen in the fuel cell cabin are simulated by fluid computation software Fluent and gas diffusion equations.Finally,distribution law of hydrogen concentration and dispersion trends are compared under different ventilation conditions of open/close doors and air vents.The simulation results show that the hydrogen concentration is higher in the top four corners of the cabin,which are the optimal places for hydrogen detection.Moreover,keep doors open can reduce the final concentration of hydrogen by about 20% under the condition of natural ventilation.When ventilation rate of single vent is 6 m3/s,the dispersion mole fraction to other cabins can be kept under a safety level of 4%,while concentration of hydrogen in the cabin can be kept at a low level.Continually increase the ventilation rate has less effectiveness to lower concentration of hydrogen.
A Mobile Phone APP for Travel Survey and its Application
DENG Bo, ZHONG Ming, CHEN Dejun, XIONG Zhuang, John Douglas HUNT
2017, 35(6): 67-77. doi: 10.3963/j.issn.1674-4861.2017.06.010
Abstract(448) PDF(0)
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Travel survey is an important data source for travel demand forecasting models.It is primarily relying on artificial completed,which is time-consuming and laborious.Besides,its data amount is too small to be used in actual situations.To solve these problems,a mobile phone APP for travel survey is developed and its application on traffic planning is developed.Currently,a person who stays indoor cannot be accurately located by mobile phone data.In this study,velocity and accuracy of trajectory data of mobile phone are used to identify whether the person stays or not.Then "stay points" are merged according to distance.People can use this APP to add their travel information on these "stay points".Compared with a travel survey in Qingpu district in Shanghai,the recognition accuracy of the APP is 96%.This method can objectively collect spatial location and time information of travel activities of people,and is of great significance to improve the accuracy of travel forecasting models.
Transportation Planning and Management
A Decision Method for Route Selection of Ships Based on Prospect Theory and TOPSIS
LYU Zhengxiang, YANG Xing, CHEN Shuzhe, HU Jiaying, MA Jie
2017, 35(6): 78-84. doi: 10.3963/j.issn.1674-4861.2017.06.011
Abstract(449) PDF(2)
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In order to make route selection of ships reflects subjective preference of decision makers,a method based on prospect theory and the theory of order preference by similarity to ideal solution (TOPSIS) is proposed.According to characteristics of route selection,a value function and a prospect value matrix are proposed.Differences of ship types are considered,then different reference points are set.TOPSIS theory is conducted to evaluate relative proximities for different routes,the steps based on value differences within each index from negative to positive values.All options consider different sensitivity to loss of decision-makers,and in accordance with relative proximity,they are ranked from superior to inferior.To evaluate the proposed model,a case study of three routes in a port is analyzed.Route selection of different ship types under different sensitivity to loss is studied.The results show that the optimal option varies with different subjective preferences of different decision-makers.It can prove that subjective preferences of the decision maker have a greater impact on route selection.
Modeling and an Analysis of Safety Perception of Online Car-hailing Passengers Based on a Structural Equation Model
CHEN Yu, WANG Ying, NIE Qiong, ZHENG Jingyue, DING Chuan
2017, 35(6): 85-92. doi: 10.3963/j.issn.1674-4861.2017.06.012
Abstract(548) PDF(6)
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In recent years,online car-hailing service has been developing rapidly.However,safety problems hidden in its operation is becoming increasingly prominent.In order to study safety perception of passengers,this paper illustrates safety problems from three perspectives using a fishbone diagram:traffic safety,information safety,and personal and property safety.Based on it,a questionnaire survey is designed and conducted.In order to present complex relationships between different latent variables,a logical framework based on structural equation model (SEM) is developed,which reveals influencing paths and significance of personal characteristics,accident experiences,safety knowledge,and risk propensity on safety perception of online car-hailing passengers.The results of SEM indicate that accident experiences,safety knowledge,and risk propensity of passengers have great influences on safety perception when they have online car-hailing.Personal characteristics such as gender and income also have impacts.The results can provide theoretical references for policy-making on safety management of online car-hailing.
An Analysis on Characteristics and Behaviors of Traveling by Bike-sharing
RAN Linna, LI Feng
2017, 35(6): 93-100,114. doi: 10.3963/j.issn.1674-4861.2017.06.013
Abstract(561) PDF(5)
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Studies of travel behaviors helps to formulate more effective policy measures for traffic construction,management,and control.Bike-sharing is developing as a new green travel mode,which facilitates travel of people.However,due to its rapid development and lack of traffic planning,there are problems occur in the developing process.Therefore,it is necessary to study the travel behavior of bike-sharing.A questionnaire survey is conducted and 621 valid data is collected.Based on the data,factors influencing people using bike-sharing are obtained,and characteristics of their travel are analyzed.A binary Logit model is developed and SPSS is used for computation.Results show that in comparison,women,young people,and people with a higher level of education are more inclined to use bike-sharing.Among these factors,the level of education is the most significant one.Besides,monthly income is removed from the variables in the model,which indicates that this factor has no significant effect on bike-sharing.
Intention of Urban Residents to Use Public Bike-sharing System: A Case Study in Hefei
YAN Ran, CHU Jinlong, YANG Xingang
2017, 35(6): 101-107,114. doi: 10.3963/j.issn.1674-4861.2017.06.014
Abstract(404) PDF(0)
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In order to study factors that have influences on intention to use public bike-sharing system,and relationships among them,an extended model of is developed on the basis of theory of planned behavior (TPB).In this model,latent variables are attitude,subjective norms,perceived pleasure,flexibility and convenience,and behavioral intention.By analyzing reliability and validity of data obtained from questionnaires,a structural equation model (SEM) of intentions to use bike-sharing is developed,and relations among the factors are obtained.The results show that TPB can be applied to explain the intention of urban residents to use bike-sharing.Subjective norms have the most significant impact on the intention,following by attitude,then by perceived pleasure,while effects of flexibility and convenience is relatively insignificant.
A Study on Mechanical Properties of Filling Composite Pavement under Different Surface Combination Types
WEI Xiaohao, LUO Sang, LIU Liu, TIAN Jiahao
2017, 35(6): 108-114. doi: 10.3963/j.issn.1674-4861.2017.06.015
Abstract(393) PDF(0)
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Considering stress and deformation of pavement in design of composite pavement structure,combined with an elastic layered theory system,the ABAQUS software is used to establish a mechanical simulation model of composite pavement with different surface combination types.The simulation including circumstances of surface and middle layers both using modified asphalt concrete or cement mortar pouring concrete;surface layer using modified asphalt pavement-middle layer using cement mortar pouring concrete;surface layer using cement mortar pouring concrete + middle layer using modified asphalt pavement.The mechanical properties,i.e.bottom stress,strain,and deflection of road surface,of different combination types of pavement are computed.Results show that compared with the common pavement structure,when surface and middle layers both using cement mortar pouring concrete,tensile stress of bottom layer and deflection of road surface are reduced by 25.7% and 50.9 %,respectively.When cement mortar is poured into middle layer,the relevant properties are also better than common pavement structure.When cement mortar is pouring into surface layer,the maximum tensile stress has greater influences than which of common pavement structure.It suggests that composite pavement has best mechanical properties when cement mortar is used for both surface and middle layer.When cement mortar is used for middle layer is less good,while it is only used for surface layer is not recommended.