Andyyl Q ??‌资–™/Transport-Engineer...Australia relevant to the traffic engineering. Career Episode I (a) Introduction : Career Episode Title : in

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  • Career Episode I (a) Introduction Career Episode Title: Research on Characteristics of Taxi Traffic in Shenzhen Based

    on GPS Data Duration of Career Episode: from March 2007 to June 2007 Site: Tongji University (except for two weeks in Shenzhen) Organization: Tongji University Title of position: Member of the research team of Transport and traffic engineering

    faculty, Tongji University (b) Background CE1.1 Nature of the project: (Design of my bachelor degree diploma) In China, with

    the rapidly development of the public traffic, taxis traffic become more and more important because of its convenience. However the management of the taxis is very disordered and needs improvement. Thus, it is very significant to research on the characteristics of taxi traffic by tracking their routes and locations of pick-up and drop-off passengers. Since the taxis equipped with GPS in this project are called Floating Cars, therefore, the data collected from them is called Floating Car Data.

    CE1.2 Objective: The objective of this project is to analyze the characteristics of taxi traffic in Shenzhen (one city in China) from the data collected by taxi equipped with GPS and map-matching.

    CE1.3 My duties: In the project, I shall use my fundamental knowledge of the traffic engineering and basic computer technology to alter, filter, manage and analyze the data, and from the data I shall research on the characteristics of taxi traffic in Shenzhen, including spatial distribution of taxi trip demand, distribution of trip distance, distribution of trip time and so on. Finally, I shall put the outcomes of traffic distribution onto the graphics with the software Mapobject. Furthermore, to achieve a clear view of the function of GPS in this project, I went to Shenzhen and observe the taxis equipped with GPS in practice.

    CE1.4 Organizational structure: In the team of this project, the Dean of our faculty acted as the tutor and leader, one member acted as the programmer to receive the GPS data, and another two including me acted as the analyst and designer.

    (c) Personal Workplace Activity CE1.5 In the project, the data collected from GPS equipped on a large number of taxis

    in Shenzhen should be received by the computer located in the lab of Tongji University. Every data collected includes the fields of date, time, ID of car, latitude of car location, longitude of car location, speed, azimuth angle, state of load, state of GPS equipment. I used the software Visual Basic to create a database of all the data and then sorted them with the sequence of car ID, date, and time. Since that, it is easy to get the route of one taxi by the data of its locations at one point of time and the next point of time.



  • CE1.6 Then the data should be pretreated by the two analysts (including me) by eliminating the incorrect or unsuited (to the research) data, such as the data whose latitude and longitude exceeds the road-map of Shenzhen or the data collected from a non-working taxi. Then, I converted the data from latitude-longitude coordinates to Cartesian coordinates under the Gauss projection, and the progress of pretreatment was achieved by the computer program. Then the data of taxis routs and locations of pick-up and drop-off passengers should be located onto the road in Shenzhen under the particular algorithm.

    CE1.7 I always checked the error logging report which broke off the course of data-pretreatment. I discussed with the programmer about the problem happened in the program once a week, to achieve a better rate of work. Meanwhile, the programmer also told me that some problems were not caused by the program but the GPS equipment. Then I turned to the resource database to search for the reference, and learnt that the data collected from GPS may be incorrect since the signal of GPS equipment may be interrupted and delayed in the particular area covered by the high-rise and trees.

    CE1.8 After the treatment of the floating car data, I selected the data from January to April, 2007 to analyze the mean operating ratio (the state of operating means taxi drivers work), unloaded ratio (the state of unloaded means there is no passenger in the taxi) and todays best quantity of taxis in Shenzhen and I applied the software Microsoft Excel to get the diagram of the outcome distribution. From the diagram, I found out that the operating ratio of taxis in Shenzhen had dropped from 90% to 75% after 1st, April. Then I logged on the website of the Traffic Office of Shenzhen and checked out that the new policy applied in the April, 2007 aimed to release the pressure of the taxi driver by decreasing the tax rate, therefore, the mean operating rate of taxis dropped approximately 15% relatively. From the diagram of the unloaded ratio, I analyzed and found out that the trend of the outcomes meets with the condition of the traffic peak in a day and in a week. The outcomes in this step could help the relative departments of government to make a decision when carrying out a policy.

    CE1.9 Then in the March, 2007, I began to track the routes and locations of pick-up and drop-off passengers by the state of load field of the data collected and the routes carried out on the road-map. In the state of load field, the figure 0 means no passenger and 1 means there is at least one passenger in the taxi. Thus, for example, from the condition that this field of one taxi data changes from 0 to 1, I could determine the interval of the picking-up course on the road-map. Since that, I could match all the taxis locations of pick-up or drop-off passengers to the road-map of Shenzhen, and analyze the distribution of the locations, spatial distribution of taxi trip demand, distribution of trip distance and distribution of trip time with my basic knowledge of traffic engineering and standard and codes of traffic engineering in China. Later, I applied the software Mapobject to express the distribution



  • of the locations in color on the map as below (each color means a different range of distribution).

    Figure 1.1 Distribution of taxis locations of pick-up CE1.10 Then I began to work on my progress report in the end of the March, 2007.

    Meanwhile, I joined some lectures organized by the Faculty of Survey to improve myself in this area. In the middle of the April, 2007, I wondered whether the travel distribution by taxi in Shenzhen meets with the functions of the different branches of road network in Shenzhen. Then I enquired the tutor and discussed with the teammate about this point of view, and they encouraged me to do a further research. After searching for the foreign reference on Internet (some e-journals in English) and analyzing the outcomes, I worked out a report to explain this point of view and its significance and feasibility in theory.

    CE1.11 On 5th May, 2007, I went to Shenzhen to observe the taxis equipped with GPS in practice. I tested about 10 GPS equipments on their stability and I chat with the taxi drivers to gain a more overall concept of their function. Nevertheless, I also asked the question of the application of GPS in their taxis would interrupt their normal lives and privacies and the general situation of taxi traffic demand in Shenzhen. To my satisfactory, most drivers hold an appreciative attitude to the project. After the practice, I also have a general image of the cost of applying GPS technology in taxi traffic management.

    CE1.12 In the middle of June, I worked out the final vision of this project report and reported in oral in the presentation. The report was approved by my tutor and I got a grade of Good of it.

    (d) Summary CE1.13 As an analyst in the project, I applied my computer technology to treat and



  • manage the GPS data, and applied my fundamental knowledge of traffic engineering to analyze the taxi traffic characteristics in Shenzhen.

    CE1.14 Through the analysis and treatment of the data collected from the taxis equipped with GPS, the outcomes of the overall project, could be a support to the taxi traffic management and control and decision-making in the urban traffic management.



  • Summary Statement of Competency Elements Competency element How and Where demonstrated Paragraph reference in

    Career Episode ET1.1 I applied mathematics and

    engineering method to pre-treat the data and process the application.

    CE1.6, CE2.6, CE2.9, CE2.11

    ET1.2 I turned to the relevant resource database to search for the reference about GPS application in traffic management and about the urban transport design.

    CE1.7, CE2.7

    ET1.3 I perceived possible sources of error, and eliminated the wrong data.

    CE1.6, CE1.7

    ET1.3 I checked the error report to find out the errors in the program.


    ET1.4 I got general knowledge of taxi traffic in Shenzhen and the society significances of the project to them.


    ET1.4 I had the basic knowledge of urban transport design and the application of it in society.


    ET2.1 I identified the influence carried by the tax policy to the operating ratio of the taxis in Shenzhen.


    ET2.1 I identified the measures of activities determine the trip generation of transportation model.


    ET2.2 I identified the practical problem that the GPS data would be affected by the geographical factors

    CE 1.7

    ET2.2 My pair and I compared four methods for traffic assignment and selected one by effects and limitations.

    CE 2.8

    ET2.3 I acted as an analyst conducting the design and read

    CE1.4, CE1.7, CE2.6. CE2.9

  • the program report to ensure the