1 / 39

A Novel Accessibility (Serviceability) Measure using Travel Time and Space Syntax Indices

A Novel Accessibility (Serviceability) Measure using Travel Time and Space Syntax Indices. Lee, Seungjae Lee , Byoungwook. 5. Contents. 1. Introduction. 2. Definition of Serviceability. 3. Basic Concept. Measuring Serviceability

melantha-ganis
Download Presentation

A Novel Accessibility (Serviceability) Measure using Travel Time and Space Syntax Indices

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. A Novel Accessibility (Serviceability) Measure using Travel Time and Space Syntax Indices Lee, Seungjae Lee , Byoungwook

  2. 5 Contents 1 Introduction 2 Definition of Serviceability 3 Basic Concept Measuring Serviceability with Space Syntax and Travel Time 4 4 Applying to Kangnam area 6 Conclusion

  3. Introduction • Seoul Public Transport Reform Begins from July, 2004 Paradigm Shift on Transport Policy Car-oriented People-oriented Public transport-centric Private car-centric Seoul PublicTransport Reform Construction of transport facility -centric Environment-friendly Operation & Mgmt. of transport facility-centric Development-oriented

  4. Introduction ExclusiveMedianArterialBusLane

  5. Introduction Exclusive Median Arterial Bus Lane Lack of dwelling area due to street facilities Interruption / outer lane stop Convenience improvement Securing punctuality Bus speed increase Exclusive lane for bus Separated dwelling area for bus passengers

  6. Introduction • MEDIAN ARTERIAL BUS LANE IN SEOUL

  7. Introduction • MEDIAN ARTERIAL BUS LANE IN SEOUL

  8. Introduction • Accessibility (Serviceability) is being focused more attention by planners recently • Seoul City has redesigned the Bus Network systems to Hierarchical (corridor and feeder) systems • Also implemented the bus network system with “Median bus lane” for improving the bus speed and access • Need to measure the serviceability for evaluating how much the serviceability is improved

  9. Definition of Serviceability • General meaning of Accessibility • Ability to obtain goods, services and activities • How fast CBD or Critical Area is approached • Serviceability in this study • Ability to approach to bus stops • Can represent as a meaning of “Serviceability” • General meaning of Serviceability is “the quality of being able to provide good service by public transport”

  10. Travel time Previous bus line Hierarchical line Travel time of Feeder line Travel time of Corridor line In-vehicle time of Previous line with feeder In-vehicle time of Hierarchical line with corridor Waiting and transfer time Destination Origin Distance Feeder Corridor Feeder Transfer Critical Point Transfer Basic Concept

  11. Measuring Serviceability with Space Syntax and Travel Time • Space syntax is the technique to analyze the connectivity of urban or architectural spaces. • Has been applied to analyzing movement in indoor spaces or pedestrian paths (not in transport network). What is Space Syntax?

  12. Space Syntax Representation The difference of axial lines and transportation networks A C B

  13. Space syntax Analysis Seoul network

  14. Hierarchical Network Configuration • Movement can be described in an abstracted form using its topology. • Topological description helps focus on the structural relationship among units. • For example, pedestrian movement can be described using network of simple lines without considering the details such as sizes of forms, number of people and speed of movement.

  15. 4 2 1 5 6 3 Hierarchical Network Configuration • Topological description of streets network

  16. 1 2 3 4 5 6 Hierarchical Network Configuration • Hierarchical structure of a street • Representing each component with a node and a turn with a link connecting their respective nodes step 3 step 2 step 1

  17. Hierarchical Network Configuration • This relationship is described as a variable called depth. • Depth of one node from another can be directly measured by counting the number of steps (or turns) between two nodes.

  18. Hierarchical Network Configuration • Total Depth(TD) • TD1 = 1 x 2 + 2 x 2 + 3 x 1 = 9 TDi : the total depth of node i s : the step from node i m : the maximum number of steps extended from node i Ns : the number of nodes at step s

  19. 1 2 3 4 1 2 3 4 Hierarchical Network Configuration • Mean Depth(MD) = TD / (k-1) • Normalized Depth(ND) ※ k : the total number of nodes 2 3 4 1 step 1 a. completely symmetrical network 4 1 step k -1 2 3 b. completely asymmetrical network

  20. Calculation of Space Syntax Integration Value Representation of axial lines E 2 7 3 9 1 4 3 5 8 S 6

  21. 7 2 9 1 9 2 4 5 5 1 2 5 5 6 7 9 3 7 4 5 8 7 6 7 3 8 9 1 2 4 1 1 7 4 9 9 7 2 6 6 8 6 2 5 1 3 8 8 9 4 5 4 3 4 6 1 3 8 3 2 8 6 8 2 7 3 6 7 1 8 4 9 5 6 3 1 3 2 9 4 5 Calculation of Space Syntax Integration Value Mapping schematic route connectivity onto a graph step 3 step 2 step 1 step 3 step 2 step 1 step 3 step 2 step 1

  22. Calculation of Space Syntax Integration Value Computing depth from each road

  23. Measuring Serviceability with Space Syntax Computing “Inner Product” • We use the Bus stop as a base. But Base Unit of Space Syntax is “Axial line” • There are some problems to change the results according to the location of turns. • So we use “Inner Product” based “Link”

  24. Measuring Serviceability with Space Syntax Computing “Inner Product” • Assuming Space Syntax’s axial line is affected by the adjacent lines. (right and left lines crossing Space Syntax Axial.) • We can compute below • Point to Point • Point to all

  25. Measuring Serviceability with Space Syntax Computing “Inner Product” • Assuming this network • Each actual line has each Space Syntax value “a0, a1, a2,‥‥, ak-1, ak” a1 a2 a3 ak-1 ak ‥‥‥‥ a0 ‥‥‥‥

  26. Measuring Serviceability with Space Syntax and Travel Time Computing “Inner Product” • Computing as below : Inner product between i & i+1 : Value of axial line i : weighting factor : Number of total crossing line Where, ,

  27. 5 7 11 8 9 Measuring Serviceability with Space Syntax and Travel Time Example of Computing “Inner Product” • Assuming simple network Value of space syntax IP5-7 IP7-11 IP11-8

  28. Measuring Serviceability with Space Syntax and Travel Time Computing serviceability • Computing as below • Where, Sbi,j = serviceability from i to j IPi,j = Space Syntax value using Inner Product from i to j TTi,j = Travel Time from i to j • α and β can be estimated for weighting the Sb function or a bi-criteria method can be used to calculate the Sb function in a general purpose

  29. Measuring Serviceability with Space Syntax and Travel Time Measuring Order Judgment of Serviceability Travel time with Transfer Computing Inner Product Bus Line’s Space Syntax

  30. 2KM 7 8 5KM 4KM 4KM 5KM 3KM 6KM 4KM 1 2 3 4 5 5KM 6 9 Measuring Serviceability with Space Syntax and Travel Time Example of Proto-type Networks Speed : 20km/h

  31. Measuring Serviceability with Space Syntax and Travel Time Results of Proto-type Networks 8 8 8 7 8 9 9 9 8.66 8.66 8.66 9 9 9 1 2 3 4 8.66 8.66 8.66 9 9 5 9 9.67 9.67 6 9 11 11

  32. Measuring Serviceability with Space Syntax and Travel Time Results with Travel Time of Proto-type Networks * * * Average value

  33. Measuring Serviceability with Space Syntax and Travel Time Results with Travel Time of Proto-Type Networks

  34. Applying to Seoul Comparing Bus line accessibility between before and after • Comparing between before and after • Using Seoul city’s speed date and real distance from a bus stop to a bus stop* • 20km/h with Median bus lane, others 15km/h which are the mean speeds of Seoul’s networks • Measuring how the Serviceability is improved * www.bus.go.kr

  35. Applying to Seoul(Kangnam) • Before

  36. Applying to Seoul(Kangnam) • After

  37. index Inner Product Travel Time(min) Before After Before After Kangnam St. N a m b u Bus Terminal Inner Product Travel Time Inner Product TravelTime 37.48 35.71 16.93 15.74 88.97 96.78 24.65 26.97 Jamsil Express Bus Terminal Inner Product TravelTime 92.35 76.98 30.83 22.71 National Univ. of Education Inner Product Travel Time Apgujeong 117.81 77.22 29.43 23.42 Inner Product TravelTime 110.12 100.87 26.5 25.22 Applying to Seoul(Kangnam)

  38. Conclusion • Developed the methodology of measuring serviceability using Space Syntax and travel time measures • We compared with Before and After bus network system to use some of selected bus lines in Kangnam area • This method has a limitation due to its complexity • If IP(Inner product) and Travel Time are small, that it means serviceability is good. • Hierarchical bus network system is more accessible than the previous bus network system

  39. Thank You !

More Related