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					Public Transport Network
  Design and Appraisal
    - a case study of Porto


       Álvaro Costa, Pedro Abrantes and Oana Grozavu Santos
            Faculty of Engineering, University of Porto

        19th Annual International EMME/2 Users’ Conference
                 Seattle, 19-21 of September, 2005
                       Contents
1.  Introduction
2.  Re-designing bus network
3.  Network Appraisal Methodology
4.  Impact of LRT Network
5.  Impact of Strategic Bus Network
6.  Local vs. Global Accessibility
7.  Global Efficiency Indicators
8.  Complementarities between EMME/2,Enif and
    ArcView
9. Conclusions
10. Further Research
Introduction
  • Porto Metropolitan Area pop.: 1.2 mi

  • New Light Rail (Metro do Porto)

  • New integrated ticketing system
    (Andante)

  • Need to re-design the bus network to
    improve integration and efficiency

  •    New network design based on
      “professional judgment” (heuristic
      method?)

  • FEUP was commissioned to:
        • evaluate its public
          acceptability and efficiency
        • suggest improvements
                               Introduction
• Starting point: existing STCP bus
  network (red): 81 bus lines (to be
  cut down to 50)

• Driving force: introduction of the
  new light metro network (blue)

• Problem: Guaranteeing public
  acceptability and increase
  efficiency (heavily constrained
  problem, but poorly defined
  constraints)

• Solution: Iterative, piece meal,
  client-driven approach (“trial &
  error”) to ensure feasibility of
  solution = optimization in the
  real world

• Strong emphasis on GIS analysis
  of results.
                Re-designing bus network

• Design criteria:
   – Short lines
   – Modal integration
   – Homogeneous
     frequencies (10min)
   – 20% veh-km reduction
• Result:
   – Decrease in radial
     services
   – Increase in orbital
     services
                            Change in bus
                            service
                            frequency
                            (blue = increase)
                    PT Modeling Approach
• Public Transport
  Assignment Model
  (EMME/2)


• Detailed zoning system: 350
  zones covering an area with
  aprox. 1 million inhabitants
  (City of Porto: 105 zones and
  350 000 inhabitans)

• Household travel survey from
  year 2000. Fixed demand

• The match between the two
  zoning systems was done
  applying a gravity-type model
               PT Modeling Approach

Network Characteristics:

  –   350 centroids
  –   3266 regular nodes
  –   8051 links
  –   7 modes
  –   9400 transit line segments
  –   140 lines: 81 present bus lines, 50 future bus
      lines, 4 metro lines, 4 train lines, 1 elevator
                 PT Modeling Approach

• Network Scenarios:
   – 10 (Reference case): Current STCP Network + Suburban
     Railways
   – 20: Reference Case + LRT
   – 30: STCP Strategic Network + Suburban Railways + LRT
   – 3x: Modifications of STCP Strategic Network + Suburban
     Railways + LRT


• Accessibility analysis and efficiency analysis
   –   Impact of LRT network (Scenario 20 vs. 10)
   –   Impact of STCP Strategic Network (Scenario 30 vs. 20)
   –   Impact of the new transport system (Scenario 30 vs. 10)
   –   Impact of the modifications on the Strategic Network
                Network Appraisal Methology

• Accessibility indicator (GIS plots) :
  Average generalized travel time by destination zone
     GTT ij    WalkTij    WaitTij    TransferT ij    InVehTij

                   (GTT     iD    TiD )
       GTT D       i

                     T  i
                             iD




• Efficiency indicators:
  Fleet size, Veh-kms, Total trips (operator)
  Pax-kms, travel time, walk time, number of interchanges
  (users)
              Impact of the LRT Network    Mapa nº 3
                                           dTT média global - cenário 20 vs cenário 10




  Change in accessibility
  between scenarios 10 and 20

• As expected, LRT brings about
  significant travel time
  reductions (up to 12 min)

• Greatest benefits along LRT

• Large gains up to a significant       Amp _con c.shp
                                        Linh as m etro_ a.shp


  distance from LRT, because of     dTT20 -1 0
                                        -30 - -1 6
                                        -16 - -8



  bus-LRT difference in speed
                                        -8 - -4
                                        -4 - -2
                                        -2 - -1
                                        -1 - -0.5
                                        -0.5 - 0 .5


  (25km/h vs 13km/h)
                                        -0.5 - 1
                                        1-2
                                        2-4
                                        4-8
                                        8 - 16
                                        16 - 3 0
               Impact of the LRT Network
  Change in bus passenger flows
  between scenarios 10 and 20

• General reduction in bus pax
  flows

• Small increases in certain
  suburban/orbital routes

• Potential complementary role of
  bus in new network
                Impact of the Strategic Bus  Mapa nº 4
                                             dTT média global - cenário 30 vs cenário 20



                         Network
   Change in accessibility between
   scenarios 30 and 20

• Significant travel time increases (8
  min): poorer coverage or service
  transfer to private sector

• Significant gains in some suburban
  zones (10 min): improved LRT access,
  successful integration ☺

• Gains from metro outweigh losses
  from new bus network in nearly all
  zones (special zones treated later)          Amp_conc.shp
                                               Linhas metro_a.shp
                                         dT T30-20
                                               -30 - -16
                                               -16 - -8
                                               -8 - -4


• Policy implication  Metro + SN must
                                               -4 - -2
                                               -2 - -1
                                               -1 - -0.5

  be introduced at same time                   -0.5 - 0.5
                                               -0.5 - 1
                                               1-2
                                               2-4
                                               4-8
                                               8 - 16
                                               16 - 30
              Impact of the Strategic Bus
                       Network
  Change in bus passenger flows
  between scenarios 30 and 20

• Reduction in radial flows, esp.
  around city centre, due to
  reduced frequency

• Significant increases in orbital
  flows, esp. towards main metro
  interfaces

• Explains gains away from LRT
  route  bus services play an
  important role as feeders to LRT
              Impact on the pattern of trip
                      interchanges
  Change in transfer boardings
  between scenarios 10 and 30
  (red=increase)

• Concentration of interchanges
  around key metro stations

• Bus increasingly becomes a
  feeder mode to LRT. Bus-bus
  transfers decrease significantly

• Policy implications:
   – Improve interchange facilities to
     take full advantage of new mode
   – Minimize distance between bus
     and metro stops
               Local vs. Global Accessibility
                                      Análise da Acessibilidade a Partir da Zona 190 (5-3)




• Problem: Some zones lose
  accessibility from sce. 10 to
  30

• Further investigation showed                          #
                                                        Y  #




                                          Linhas metro.shp
                                     z190_53.s hp



  inconsistencies in network
                                          -24 - -12
                                          -12 - -6
                                          -6 - -3                    190
                                          -3 - -1
                                          -1 - 1



  design:
                                          1-3
                                          3-6
                                          6 - 12
                                          12 - 24
                                          Subseccoes ine.shp

                                         Análise da Acessibilidade a Partir da Zona 190 (7-3)
    – Zones furthest away from
      metro miss out the most with
      the new bus network

    – Those zones also happen to
      be important centers for              Linhas metro.shp

                                                               #
                                                               Y
      surrounding neighborhoods
                                            Linha_39d_v.s hp     #




                                            Linha_39d_i.s hp
                                       z189_73.s hp
                                            -24 - -12
                                            -12 - -6
                                            -6 - -3
                                            -3 - -1
                                            -1 - 1
                                                                      190
                                            1-3
                                            3-6
                                            6 - 12
                                            12 - 24
                                            Subseccoes ine.shp
              Local vs. Global Accessibility
                                                                                 Time vs Distance


   Diagrams attempt to illustrate the
                                                                     45

                                                                     40

   problem                                                           35         Bus
                                                                                Bus+Metro
                                                                     30




                                    Time elapsed
• The new bus network improves
                                                                     25




                                                   (min)
                                                                     20

  access to metro stations, which in                                 15


  turn greatly improve access to                                     10


  distant parts of the city                                           5

                                                                      0
                                                           -4   -2        0           2             4          6   8   10

                                                                              Distance from Origin zone (km)

• Yet, reduced network coverage
  decreases local accessibility

• As we started by looking at the
  whole metropolitan area, this
  problem went nearly unnoticed

• Policy outcome: strengthen local
  bus services
               Global efficiency indicators – User
                           perspective
• 3% mean travel time decrease               30                         34.95
  from sc. 10 to 20




                                  Scenario
                                             20                             34.98
• Constant travel time from 20
  to 30                                      10                                                          36.16


• 1.5% mean travel distance                       34       34.5         35          35.5            36       36.5


  decrease from sc. 10 to 20                           Average generalized travel time (min)


• 1.5% mean travel distance                                                                                 bus

  decrease from sc. 20 to 30     Scenarios
                                             30               154,650                  36,352               metro



• Notice significant pax-kms                 20                   162,949                  33,347


  transfer to metro due to new
                                             10                     198,951
  bus network (+10%)
                                                  0      50,000      100,000 150,000 200,000 250,000
                                                                            Pax-kms
                Global efficiency indicators – User
                            perspective
• Metro does not produce an                      30                      1.41
  increase in av. interchanges




                                    Scenario
                                                 20                                                     1.44
• New bus network actually
  reduces interchanges                           10                                                              1.45

                                                      1.39   1.4       1.41     1.42    1.43      1.44         1.45     1.46
• But at the cost of greater walk                                   Average number of boardings
  access time                                                                 per trip



• Still, no increase in travel
  time                                Scenario
                                                 30                                                                     7.91



                                                 20                              7.17



                                                 10                                            7.45


                                                      6.60   6.80      7.00     7.20    7.40          7.60     7.80      8.00

                                                                              walk time (min)
            Global efficiency indicators – Operator
                          perspective
• 6% decrease in fleet size                 Fleet size     Veh-kms
  requirements                                           (AM peak hr)

• 4.2% decrease in morning peak     Bus_0      517          7676

  hour veh-kms traveled             Bus_1      485          7350
                                    delta    -6.0%          -4.2%
• Conclusion: Significant savings
  achieved, while maintaining
  or improving accessibility by
  applying simple network
  design rules

• “Operator happy, passengers
  happy”
               EMME/2 - Enif - ArcView
• ArcView is a great help in the construction of EMME/2
  network files
• ArcView is a good tool for “translating” in a friendly
  image the results of the assignments (especially OD
  pairs related data)
• In both cases, Access is a priceless help

• Enif is a useful tool for analyzing data regarding
  interfaces, boardings, alightings, flows on links
                          Conclusions
• The methodology is understandable to decision makers

• Benefits from LRT line are significant, and spread
  beyond the route

• Scale of benefits depends on bus service design  bus
  plays an important feeder role in the LRT network

• It is possible to achieve significant gains in accessibility
  and productivity by re-designing the bus network for
  better integration with LRT network

• Nevertheless there is a trade-off between local and
  global accessibility in some areas, which is not visible
  when analyzing accessibility across the whole area
                    Future research

• Schedule the implementation

• Incorporate elastic demand model

• Introduce outstanding operators and differentiated fare
  system

• Develop optimization algorithms to find the “optimum
  network”

• Test the impact of other policy measures, e.g. bus
  priority
               Questions & comments

Álvaro Costa < afcosta@fe.up.pt>
Faculdade de Engenharia da Universidade do Porto

Oana Grozavu Santos <oana@fe.up.pt>
Faculdade de Engenharia da Universidade do Porto

				
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