2015 No. 6

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Developments and Prospects of Intelligent Water Transport:A Review of the Symposium on Intelligent Water Transport, in Conjunction with the 10th Annual Meeting of China ITS
JIANG Zhonglian, CHU Xiumin, YAN Xinping
2015, (6): 1-8. doi: 10.3963/j.issn 1674-4861.2015.06.001
Abstract(202) PDF(11)
Abstract:
Intelligent Water Transport has become one of the important areas of modern waterway transport re-search.This paper presents a review of the symposium of Intelligent Water Transport in conjunction with the 10 th annual meeting of China ITS.The recent developments of Intelligent Water Transport are summarized and discussed,which in-clude security technology of polar navigation,intelligent service system of inland waterway,intelligent water transport, resources management of ports and marine electric propulsion system.The intelligent ship,information communication technology (ICT)and connected ships are also identified as the highlighted trends of intelligent water transportation areas and their perspective are also presented.
A Review of Existing Methods and the Perspective of Studying the Features of Pedestrian Traffic Flow
ZHOU Jibiao, DONG Sheng, CHEN Hong, ZHANG Minjie
2015, (6): 9-18. doi: 10.3963/j.issn 1674-4861.2015.06.002
Abstract(198) PDF(14)
Abstract:
Taking the pedestrian traffic flow characteristics as the object,this paper summarizes the development history and current studies on the features of pedestrian traffic flow,and analyzes its development trend.Firstly,data col-lection methods for studying pedestrian traffic flow are reviewed such as manual investigation method,video detection method,Voronoi method.Secondly,the macroscopic and microscopic features of the pedestrian traffic flow are summa-rized.Meanwhile,the relational diagram and overall motion characteristics of pedestrian traffic flow are illustrated,then speed features of individual pedestrian and interactions among individual pedestrian are discussed.The micro-features of pedestrian traffic flow is a natural reflection of its macro-features.Review results indicate that various aggregate behaviors of pedestrian flow dynamics results from non-linear interactions between pedestrians.Pedestrian traffic flows show 3 dis-tinct features:diversity of travel purpose,self-organization of travel behavior and avoidance of the collision within travel process.Pedestrian speed decreases with the increase of density;when pedestrian density is lower than 1.0 ~2.0 p/m2 , pedestrian traffic flow is in the complete free state,which means the speed is not affected by the density,but only affectedby personal preference,comfort level and travel purpose.When the pedestrian density increases to 4~5 p/m2 ,the speed will reduce to 0.2 m/s,that means the pedestrian traffic flow is under a congestion state and it is difficult to continuously move forward.Due to the difference in gender,physiological and psychological conditions,age,trip purpose,and survey locations,the pedestrian velocity fluctuates in the range of 0.9~1.9 m/s,and the density is in the range of 1.7~7.0 p/m2 , while the maximum blocking density is in the range of 3.8~10.0 p/m2 .It is also found that data collection methods,traf-fic simulation,and traffic modeling and empirical tests related to pedestrian traffic flows will be the study trend in pedes-trian traffic flow research.
Microscopic Characteristics of Lane-Change Maneuvers Based on NGSIM
ZHANG Yingda, SHAO Chunfu, LI Huixuan, MA Xuejing
2015, (6): 19-24,32. doi: 10.3963/j.issn 1674-4861.2015.06.003
Abstract(207) PDF(14)
Abstract:
Under different lane change intention,lane-changing behavior can be divided by their microscopic charac-teristics into free-flow lane-changing (FLC)and strained lane-changing (SLC).They are investigated through statistical a-nalysis methods based on NGSIM data in this paper.In order to ensure the accuracy of the data,the parameters for a sin-gle lane change behavior are extracted based on a data smoothing process,and spatiotemporal constraint rules,which are developed to eliminate abnormal samples.This paper uses regression analyses to study the significant influence factors of lane-changing durations of FLC and SLC,and develops a semi-logarithmic model to compare them.In addition,a polyno-mial model is developed to fit the lateral trajectory,and 3 variance indicators are selected to evaluate the optimal fitting order.The results indicate that the mean duration of SLC is slightly longer than FLC.Even though the durations are af-fected by distinct factors and weights,the lateral trajectories of SLC and FLC can be fitted with similar 5th order of poly-nomial models,and the goodness of fits are both greater than 0.99.
Analysis of the Travel Characteristics of Residents in Shanghai Using the Itinerary Data Collected from Smartphones
YANG Chao, ZHU Rongrong, TU Ran
2015, (6): 25-32. doi: 10.3963/j.issn 1674-4861.2015.06.004
Abstract(209) PDF(1)
Abstract:
Travel data of urban residents is an important base for urban planning,traffic management and behavior research.Traditional methods such as face-to-face interview and paper-based questionnaire are of high cost and low accura-cy.This study develops a travel survey system based on GPS-enabled smartphones.A rule-based algorithm is proposed to extract travel information automatically from high-frequency GPS data collected by smartphones.A case study is carried out at New Tongji Village,a residential area in Shanghai.A comparison of travel data obtained from traditional question-naire-based surveys and smartphone-based surveys is also made.The results from the questionnaire survey are used to im-prove the parameters of the trip generation model based on the data from the smartphone-based survey,and the inaccura-cy in traditional questionnaire-based survey is also studied.It is shown that the overall error of the traditional survey is a-bout 33%,and the error for non-home-based travel is as high as 1 59%.Finally,travel behavior of urban residents is also analyzed based on the data from smartphone-based survey.
A Method for Estimating Origin-destination Matrix of Public Transit Based on Smart Card and AVL Data
LI Haibo, CHEN Xuewu, CHEN Zhengrong
2015, (6): 33-39,95. doi: 10.3963/j.issn 1674-4861.2015.06.005
Abstract(241) PDF(2)
Abstract:
The use of automated fare collection (AFC)systems and automated vehicle location (AVL)systems pro-vides a new way to obtain origin-destination (OD)matrix of public transit.In order to improve existing algorithms,this paper develops an improved algorithm for estimating the OD matrix of public transit using smart card and AVL data, which mainly consists of boarding and alighting location data.Based on analysis of AFC data of public transit passengers, a time correction model for smart card data is developed using the AVL data,in order to improve the accuracy of boarding locations.To optimize the inference of alighting locations,this paper divides trip chains of public transit into 2 major types,continuous and discontinuous,then proposes specific alighting inference models for them according to their distin-guish characteristics.The improved algorithm is applied to study the smart card and AVL data from the City of Suzhou, and its feasibility and validity is validated by the rationality of the results indirectly.The results show that the improved algorithm has an effective progress and easy to be programmed.It can be used to automate the analysis of passenger flows of public transit.
A Travel Data Collection Method Based on Big-data from a Smart Phone APP
YANG Yang, OU Dongxiu, HE Xiangjun
2015, (6): 40-47. doi: 10.3963/j.issn 1674-4861.2015.06.006
Abstract(186) PDF(0)
Abstract:
travel of Urban residents is one of the fundamental questions in transportation research.According to the characteristics of the current mobile phone application,this paper focuses on extracting residents'travel data from CI (Cell-ID Identify)location data generated during the interaction between mobile phone application and wireless communi-cation network.A total of 3 241 238 CI positioning data in 2013 and 2014 has been collected from"Yi Xin"App,which is then preprocessed through dimensionality reduction,discretization and de-noising.This paper develops an efficient matrix operation algorithm to extract origin/destination information and inbound and outbound traffic flow data of each residen-tial area based on the conversion of CI positioning data into standardized 0-1 matrices.Matlab is used to implement this algorithm.The results show that,comparing to circulation algorithm of data traversal search,this algorithm can achieve a higher efficiency which shorten the time from days to minutes.An index R has been presented to evaluate the integrity and authenticity of the derivate users′OD matrices.The index R of OD matrices is 1 9.1% in 2013,and 69.3% in 2014. The results indicate that the CI positioning data with higher daily data amount (10.6 in 2013 and 47.4 in 2014)has higher integrity and authenticity.However,this index only reflects the overall condition of trips from all residential areas,and the fact if this index can fully and truthfully represent travel behavior of each individual traffic analysis zone should be fur-ther studied.
A Study of On-board Fusion and Extraction Algorithm of Pedestrian under the Environment of CVIS
LI Ze, LV Nengchao, WU Chaozhong, DENG Chao, MENG Ke
2015, (6): 48-53. doi: 10.3963/j.issn 1674-4861.2015.06.007
Abstract(157) PDF(0)
Abstract:
Due to its low accuracy of detection distance and occlusion,current on-board pedestrian recognition sys-tems are not suitable for implementation at curves and intersections.In order to enhance the warning effects of vehicle on-board system,this paper developed a fusion & extraction algorithm for pedestrian identification under the environment of cooperative vehicle infrastructure system (CVIS).Pedestrian is detected by roadside and on-board cameras,and pretrea-ted by a Kalman filter.The optimal position estimation of pedestrian is estimated through spatial and temporal alignment, fuzzy association and Kalman fusion.An actual vehicle experiment platform is set up to verify the effectiveness of the pro-posed fusion & extraction algorithm.Compared to errors from the pedestrian trajectory estimated before applying the fu-sion and extraction algorithm ,the maximum absolute error reduces by 5 0 .0 0 % and absolute average error reduces by 55.56% at the X direction .As to theY direction,the maximum absolute error reduces by 40.00%,and the absolute av-erage error reduces by 62.07%.Experimental results show that the proposed algorithm improves the detection accuracy of pedestrian trajectory and enhances the warning accuracy of the system significantly.
A Study of the Optimized Maintenance Scheduling of the Bogie of Railway Transit Based on a Delay Time Model
ZHAO Yachen, CHEN Shaokuan, TONG Shuo, LIU Haidong, WANG Wenbin
2015, (6): 54-59. doi: 10.3963/j.issn 1674-4861.2015.06.008
Abstract(136) PDF(0)
Abstract:
In order to improve the efficiency of bogies of railway transit and to reduce the maintenance cost,it is necessary to optimize the maintenance scheduling.According to the renewal reward theory,the objective of this study is the minimization of average maintenance cost per unit cycle for safe operation.On the basis of the delay time theory,this study develops an optimized maintenance scheduling model for the bogies of railway transit.Based on the failure records and preventive maintenance inspection data,this study develops the delay time distribution function related to maintenance scheduling and a maximum likelihood method is used to estimate model parameters and the optimal maintenance period. Finally,this model is applied to test a subway maintenance plan as a case study.A comparative analysis between optimi-zation results and existing maintenance scheduling is carried out and used to validate the model.The results show that the maintenance cost of the bogies of the rail transit vehicles reduces by 23% when the optimized delay function is applied and combined with the group preventive maintenance.This study may serve as a reference for planning maintenance schedu-ling of rail vehicle bogies.
A Study of the Evolution of Traffic Flow Dynamic of a Disequilibrium Network
LIU Bo, ZHANG Sheng
2015, (6): 60-64. doi: 10.3963/j.issn 1674-4861.2015.06.009
Abstract(200) PDF(0)
Abstract:
To describe the cost-flow relationship of disequilibrium traffic flow,a function for modeling dynamic travel time is established considering the carrying cost and travel time.A flow model of dynamic traffic is developed based on total travel cost,path flow,link travel time and coupled with a user equilibrium model.A numerical simulation is car-ried out using a simple network and the fourth order Runge-Kutta method to test the created model.Under the elastic de-mand of dynamic model,travel cost ranges from large to small,then approaches to an equilibrium value.After a rapid in-crease of path flow,with a smaller adjusting range,it tends to approach to an equilibrium value.After a rapid increase in travel time,it gradually approaches to an equilibrium value.The travel cost of fixed demand,flow path and travel time approach to an equilibrium value after repeating adjustments several times with a small range.The simulation results show that the model can accurately describe the adjustment process of network traffic flow from one disequilibrium statue to another.
Bayesian Network Model for the Prediction of Traffic Incident Duration
MA Xuejing, SHAO Chunfu, QIAN Jianpei, WANG Tianyi
2015, (6): 65-71. doi: 10.3963/j.issn 1674-4861.2015.06.010
Abstract(113) PDF(0)
Abstract:
Traffic incident is one of the main factors that lead to traffic congestions.Through controlling methods such as real-time traffic guidance,its impacts on traffic operation can be reduced.Accurately prediction of traffic conges-tion duration is a prerequisite for effective traffic control.Based on MIT scoring functions,an S-ACOB algorithm as the core of the Bayesian network model is developed.The networks are generated from top to bottom with an ant colony algo-rithm searching for the optimal network structure.To increase the robustness of the proposed Bayesian network,a ran-dom selection mechanism for the nodes and a partial probabilistic selection model for the local structure are introduced. Through an empirical study and comparative analyses,the average precision is up to 87.82%,which is superior to the al-ternatives reported in the previous research.regarding those nods with the complete and incomplete node properties,the accuracy of the network prediction model is up to 76.97% and 93.23%.The results show that this model can effectively predict the duration of traffic congestions.
Estimation of the Duration of the Incidents at Urban Expressways Using Random Forest
YANG Chao, LI Haixia
2015, (6): 72-76,125. doi: 10.3963/j.issn 1674-4861.2015.06.011
Abstract(83) PDF(0)
Abstract:
Taking the complexity of influence factors of traffic incident duration on urban expressways into consider-ation,a duration estimation model based on random forest is proposed and developed in this paper.It attempts to provide a base for a reasonable estimation of the delays resulting from traffic incidents on urban expressways.The sample data is obtained from Shanghai Urban Expressway Monitoring Center.After data is preprocessed,the distribution of traffic inci-dent duration is analyzed.The minimum error of decision trees has been calculated through OOB data error estimation.An estimation model of incident duration is then developed.This model is then verified and its overall accuracy is found to meet the requirements as a reasonable accuracy with an average error of 6 min is achieved.It is also found that its accuracy is higher for duration within the range of 7~30 min,.The model is found to be more accurate and robust than decision-tree method.
The Effects of Side Wind on the Safety of Turning Vehicles on Bridges
CAI Xiaonan, CHEN Shengdi, JIANG Yuming, LU Jian
2015, (6): 77-81,107. doi: 10.3963/j.issn 1674-4861.2015.06.012
Abstract(114) PDF(0)
Abstract:
In order to analyze the effects of side wind on the safety of vehicles traveling on the curve sections of bridges,under the combined effects of vehicle types,road conditions,vehicle speed and wind speed,the force applied to vehicles are studied to develop a limit equilibrium equation.According to the observed data from a cable-stayed bridge in China,critical wind speed is calculated at various vehicle speeds for maintaining a safe vehicle operation.Results show that as vehicle speed increases,critical wind speed increases slightly within a certain range,then descends.Such result contrasts to previous studies which commonly believe that critical wind speed decreases with increasing vehicle speed.To further study this paradox,the relationship between vehicle speed and critical wind speed is analyzed,and the distribution range of the corresponding vehicle speed is calculated when the above paradox occurs.The conclusions from this study are helpful for presenting a comprehensive understanding of the effects of side wind on vehicle safety,and to maintain a safe operation of the bridges.
An Evaluation of the impact of metro structure onto the reliability of Network Connectivity
Yang Cheng, Wang Jiawei, Fan Wenbo, Lv Xue
2015, (6): 82-88. doi: 10.3963/j.issn 1674-4861.2015.06.013
Abstract(104) PDF(0)
Abstract:
Metro is one of the most important public transport systems in modern society.The reliability of connec-tivity is not only affected by uncertain factors (e.g.operational failures,terrorist attacks,and stampedes),but also close-ly related to network structure.To evaluate the impacts of network structure (in terms of different composition of lines) on the reliability of the connectivity of the metro network,the concept of "the importance of line connectivity" and the corresponding models are developed to study the difference (in percentage)before and after line addition/removal based on the theory of the reliability of connectivity.An order-based algorithm integrated with a judgment algorithm is used to find solutions for the proposed models.Metro Network of Guangzhou in 201 5 (i.e.a typical grid network)is selected as a case study to evaluate the impacts of line features (e.g.number of stations)on the reliability of network connectivity.The re-sults show that the Line 3 consistently has the highest connectivity importance (reaching 99.84%).As a key line,its im-portance is jointly affected by the number of transfer stations and intermediate stations.The impact of the former is more significant than the latter.It is suggested that in-depth studies and evaluations should be carried out to prioritize the poli-cies related to metro construction and maintenance .
An Analysis of the impact of Geometry Design to the safety of Interchange Ramps of Urban Expressways
LI Zhoufeng, SUN Jian
2015, (6): 89-95. doi: 10.3963/j.issn 1674-4861.2015.06.014
Abstract(81) PDF(0)
Abstract:
interchange ramps of Urban expressways,serving a large number of turning flow and with a low design standard,are accident-prone.In order to evaluate the safety of interchange ramps,accidents data and traffic flow data in recent 3 years at Puxi Expressway in Shanghai are collected.Based on vehicle behavior and interactive features of vehicles on the ramps,interchange ramps are divided into 5 study units:exit segment,connecting segment,entrance segment, left-turn ramp and right-turn ramp.For each unit,a Negative Binomial Model is developed to analyze the relationship a-mong road geometry design features,their composite effect and traffic flow,and their impacts on safety.The results show that the safety of exit and entrance segments is closely related to geometry design.Compared with right-turn ramps, the left-turn roundabout ramps are more likely to be affected by geometry design.With a higher traffic flow or longer road segment,the risk of traffic accidents is higher.However,longer exit segments are safer.The ramps that have straight line at the exit,or have long-straight downhill section at the entrance,or have a large design difference between entrance and main segment,are less safe.There are more traffic accidents taking place on left-turn roundabout ramps with small radius curve,especially when the curve is located on the exit of ramps.
A Study of Semi-active Suspension Control of Heavy-duty Vehicles Based on the Friendliness of Roads
Zhang Junning, Lu Yongjie, Han Fengzhao
2015, (6): 96-101. doi: 10.3963/j.issn 1674-4861.2015.06.015
Abstract(81) PDF(0)
Abstract:
The ride comfort and road friendliness are 2 important indicators that reflect the vehicle suspension performance. In order to improve the road friendliness of heavy-duty vehicles,based on a heavy-duty vehicle dynamics model with seven degrees of freedom,this paper builds a kinematic equations of semi-active suspension system and designs a semi-active optimal suspension controller.Aiming at the ride comfort and road friendliness of vehicles,an optimal semi-active control method for vehicle suspen-sion is put forward by taking the road surface roughness into consideration.A detailed mathematical formulation is also provided. The simulation results show that when running at the speed of 20 m/s on a road with a surface of the C level,the effective root mean square of vertical acceleration of the vehicle body reduces by 3.42% and of the driver's cabinet reduces by 46.4%;tire dam-age on the road decreases by 2.10%.The semi-active suspension control can effectively maintain the ride comfort,while reduce the dynamical force of vehicles against the road surface.Compared with the traditional suspension of passive control suspension,it can improve the suspension performance.
Analysis of Effects of Highway Alignments on Driver′s Performance Based on Simulated Driving Experiments
ZHANG Jing, XIE Lian, LIANG Xin, LYU Nengchao
2015, (6): 102-107. doi: 10.3963/j.issn 1674-4861.2015.06.016
Abstract(126) PDF(0)
Abstract:
Driver′s performance is an important indicator to measure drivers′ability to maintain a safe driving.In or-der to study the impact of highway alignments on the transversal and longitudinal driving performance,a set of simulated driving experiments are designed and carried out.The experiment road was divided into several segments according to ge-ometry.Taking driving speed and lane offset as performance indicators,statistical analysis is used to study the variation of driving performance on different road segments.The experimental results indicate that driving speed increases slightly along with the increase of curve radius;the driving speed increases first and then decreased along with the increase of gra-dient at downhill sections;lateral offset does not significantly change under different road alignments and lane offsets are affected by multiple factors,such as driving experience,driving speed and highway alignment.This study may serve as a reference for the"customized" road alignment design.
A Computational Optimization Model for the Capacity of Urban Roads
WU Xiaodan, LI Minqiao
2015, (6): 108-113. doi: 10.3963/j.issn 1674-4861.2015.06.017
Abstract(116) PDF(0)
Abstract:
Based on the analysis of computation models of road capacity,an optimization model that considers the impacts of traffic management on road capacity is developed.Based on analysis to several actions related to traffic manage-ment,a computation model using the reduction factor to consider the action related to pedestrian management factors is also developed.According to the survey data of traffic speed and volume collected on road sections in Zhuhai,the model with or without the impact of pedestrian management is verified.Vissim is used to simulate the maximum traffic volume under the above 2 conditions.The proposed optimization model of road capacity is also verified.The results show that rel-ative errors between the theoretical capacity and the simulated values under the 2 different conditions are within 5%.It is found that the optimization model that considers the actions related to the above traffic management is reasonable and it also is superior to the traditional models which only consider road and traffic condition.
A Study of Signs Design at the Unattended Freeway Toll Stations Based on Simulated Driving Experiments
CHI Jinghao, ZHAO Xiaohua, RONG Jian, XU Fei
2015, (6): 114-119. doi: 10.3963/j.issn 1674-4861.2015.06.018
Abstract(85) PDF(0)
Abstract:
With the rapid development of economy in China,the number of automobiles is increasing constantly. The traditional manual toll collection (MTC)at freeway toll stations can no longer meet the current travel demand. Therefore,many provinces and cities are testing non-stop electronic toll collection (ETC).Simulated driving is used to study the key content of this paper:the mandatory signs at unattended freeway toll stations.A case study of Xihongmen-Nanqiao toll station at Beijing-Kaifeng freeway G45 is carried out in this study.5 types of common signs are used as study objects,and 1 6 types of sign combinations are developed.Through the following 7 types of data,including questionnaire data,average speed,standard deviation of acceleration,lateral displacement,absolute deviation of parking position, number of stops and the number of decelerations,each combination is evaluated based on the following 4 indices:visibility of the signs,convenience of picking up the toll-card,comfort of driving experience,and passing efficiency,then sorted them in order from good to bad.This study proposes the best and optimum design schemes of mandatory signs at unat-tended freeway toll stations for the first time.The study results provide theoretical foundation for relevant standards regu-lating the setting of mandatory signs at such stations.
A Study of Zonal Transit Loading Index Based on IC Card Data
MOU Zhenhua, CHEN Yanyan, ZHAO Jin, ZHANG Zheng, CHEN Juxin
2015, (6): 120-125. doi: 10.3963/j.issn 1674-4861.2015.06.019
Abstract(136) PDF(0)
Abstract:
As information technology has been widely implemented onto the transit system,an extraordinary a-mount of Integrated Circuit (IC)card data and GPS data has been recorded,which can be used to quantitatively analyze the loading index of regional transit system.Based on the IC card and GPS data,this paper selects the following evaluation parameters:load factor,berthing time,boarding/deboarding volume and surplus capacity to develop a transit loading in-dex model,then develops a system for classifying zonal transit system based on their loading.According to the importance and boarding/deboarding volume of stations,this paper also develops the threshold of weighting coefficients for them. Taking Guomao and Dongdan area in Beijing as case studies,this paper calculates the loading indices of these areas,and analyses the reason for the differences between the loading of the two areas based on spatial and temporal factors.The ob-served IC card data is used to extract the boarding/deboarding information,which is used to testify the proposed model.It is found that the model can effectively reflect the loading of regional transit system.
An Optimization Model for Regional Crew Scheduling Problem Considering the Driver′s Familiarity to Bus Lines
Bo Sun, Wei Ming
2015, (6): 126-130. doi: 10.3963/j.issn 1674-4861.2015.06.020
Abstract(98) PDF(0)
Abstract:
In the case of allowing drivers to cover tasks belonged to different bus lines,a model for regional crew scheduling is proposed by considering each driver′s familiarity to different bus lines.The model meets the following con-straints such as working time,halfway rest,and mealtime.The objective is to identify the best crew scheme to minimize operating costs,and salary costs of bus drivers by taking regular and overtime work into consideration.The solutions are obtained using a tailored artificial immune algorithm which redesigned a solution code,heuristic procedure to initialize chromosomes randomly,fitness function,immune operation,etc.Finally,a numerical example is presented to calculate the best scheme and the impacts of drivers'preference for different lines on the scheduling scheme,which in turn demon-strates the effectiveness of the model and algorithm.Simulation results show that the costs of crew scheduling decrease with the increasing drivers′familiarity with one bus line.Although its scheduling cost of proposed model is much higher than the existing models,the one proposed in this paper is more realistic.
2015, (6): 131-134. doi: 10.3963/j.issn.1674-4861.2015.06.021
Abstract(63) PDF(0)
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