Theme 4 Flexible capacity operations

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Theme 4 Flexible capacity operations

  1. 1. Future of BRT: Flexible Capacity Operations Juan Carlos Muñoz Bus Rapid Transit Centre of Excellence Pontificia Universidad Católica de Chile September 20, 2013
  2. 2. Motivation: Efficiency in the use of road space www.BRT.cl
  3. 3. What can we say about bus service? Bus is critical to provide a good door-to-door transit alternative for many journeys: • Much higher network density and coverage than rail • Greater flexibility in network structure • Low marginal cost for service expansion BUT as traditionally operated, it also has serious limitations: • Low-speed • Subject to traffic congestion • Unreliable • Harder to convey network to the public • Negative public image
  4. 4. What can we say about the user? • Perceives waiting time and walking time twice as important as travel time inside the vehicle. • Avoids transferring, specially if they are uncomfortable • Needs a reliable experience • Requests a minimum comfort experience • Requests information • Needs to feel safe and secure
  5. 5. What can we say about the bottlenecks? Capacity per lane: • “Only a fool breaks the two second rule” => 1,800 veq/hr-lane • 1 Bus ≈ 2 veq => 900 buses/hr-lane Capacity per lane at junctions: • 40 – 60 % of lane capacity => 450 buses/hr-lane Capacity at Bus Stops: • Depends on the amount of passengers boarding and alighting • ≈ 20 - 40 sec. per bay => 180 – 90 buses/hr-bay
  6. 6. Buses are involved in this vicious cycle Operation cost grows Income and Population grows More cars in the city Bus Demand drops Car becomes more attractive Bus frequency drops Buses cover fewer miles per day Bus fare increases And we need to make buses attractive to car drivers… More congestion And delays
  7. 7. However, this doesn’t affect Metro as much
  8. 8. Can we provide Metro-like service with buses? • Fast • Low wait time • Comfortable • Reliable • Good information • Branding
  9. 9. Can we provide Metro-like service with buses? Transit Leaders Roundtable MIT, June 2011 • Fast • Low wait time • Comfortable • Reliable • Good information • Branding
  10. 10. Yes we can … We still believe (several pieces are already there in cities worldwide) Can we provide Metro-like service with buses? The good news are: COURAGE WILL BE REWARDED
  11. 11. IMPROVED EFFICIENCY IMPROVED SERVICE QUALITY Reduced bus costs •Less buses required •Lower cost per km Improved bus productivity •More pax/bus-day Attracts more passegers Improves revenue IMPROVED FINANCIAL VIABILITY Better buses More investment into new buses & cleaner technology Lower Subsidies Reduced private car use & traffic congestion Improved energy efficiency Reduced emissions Operational benefits •Shorter cycle time •Reliable operations •Higher productivity Increase Bus speed, Frequency, Capacity and Reliability Passenger benefits •Reduced travel time •Reduced waiting time •Higher comfort •Reliability Source: Frits Olyslagers, May 2011
  12. 12. Fast Reliable Metro Attributes Actions ComfortLow waits Main drivers Increase Speed Regular Headways Increase Capacity Increase Frequency •Segregated ways/lanes
  13. 13. Segregated ways/lanes Low Flow: Intermittent Bus Lanes Medium Flow: Bus-Only lanes High Flow and Limited Capacity: Only bus street
  14. 14. J. M. Viegas Low Flow: Intermittent Bus Lane (IBL)
  15. 15. Demonstration in Lisbon Implementation: Technical Components Installation of the Loop Detectors IBL local controller Static signalization (advance notice) Variable message longitudinal LEDs Vertical variable message signal
  16. 16. Ricardo Giesen ©
  17. 17. Without IBL vs. with IBL (51 sec) Demonstration
  18. 18. Only Bus Lanes BUS ONLY Setback! R. Fernández
  19. 19. Partial closure of streets for cars, but not for buses Closed Junction (Brussels)Closed lane (Zurich) P. Furth
  20. 20. Fast Reliable Metro Attributes Actions Comfort Increase Speed Regular Headways Main drivers Increase Capacity Increase Frequency •Segregated ways/lanes •Reduce dwell times •Fare payment off-bus •Buses with multiple doors Low waits
  21. 21. Guayaquil, Ecuador
  22. 22. Level bording in Quito, Ecuador
  23. 23. Guayaquil, Ecuador
  24. 24. TransMilenio, Bogota, Colombia
  25. 25. TransMilenio
  26. 26. Istanbul BRT
  27. 27. Istanbul BRT
  28. 28. Divided Bus Stops Bus only street? Weaving distance: 3-4 bus R. Fernández
  29. 29. Platform 2 Platform 1 Stop area 2 Stop area 1 Divided bus stop Divided rail station Platform 2 Platform 1 R. Fernández Divided Bus Stops
  30. 30. Fast Reliable Metro Attributes Actions Comfort Increase Speed Regular Headways Main drivers Increase Capacity Increase Frequency •Segregated ways/lanes •Reduce dwell times •Fare payment off-bus •Buses with multiple doors •Increase distance between stations Low waits
  31. 31. Fast Reliable Metro Attributes Actions ComfortLow waits Increase Speed Regular Headways Main drivers Increase Capacity Increase Frequency •Segregated ways/lanes •Reduce dwell times •Fare payment off-bus •Buses with multiple doors •Increase distance between stations •Express services
  32. 32. Choosing the Right Express Services for a Bus Corridor with Capacity Constraints Homero Larrain, Ricardo Giesen and Juan Carlos Muñoz Department of Transport Engineering and Logistics Pontificia Universidad Católica de Chile
  33. 33. Introduction Operación “Carretera” Operación Expresa Higher in-vehicle travel time Lower in-vehicle travel time No transfers May force some transfers Higher operation costs, in terms of $/Km Lower operation costs, in terms of $/Km Other aspects: capacity, comfort, accessibility, etc. Limited stop servicesAll stop services *Jointly operated with all stop services, assuming a constant fleet size. *
  34. 34. Objective • Formulate a model that allows to choose which combination of services to provide on a corridor, and their optimal frequencies. • Determine opportunities for express services (or limited stop) on a corridor based on its demand characteristics.
  35. 35. The Problem p1 p2 pi pn … …
  36. 36. The Problem • Different operation schemes. p1 p2 pi pn … … … …l1, f1 … …l2, f2 … …l3, f3 … …l4, f4 The goal is to find which services to offer, and their optimal frequencies. li: Line i fi: frequency of line i
  37. 37. The Model • The goal of this model is to find the set of services that minimize social costs: – Operator costs: will depend on what services are provided, and their frequencies. – User costs: • In-vehicle travel time. • Wait time. • Transfers.
  38. 38. The Model: Assumptions • Given transit corridor, with a given set of stops. • Fares are constant for a full trip. • Number of trips between stops is known for a certain time frame. • Random arrival of passengers at constant average rate. • Passengers minimize their expected travel times.
  39. 39. The Experiment • Steps: – Defining network topology. – Defining demand profiles. • Load profile shape. • Demand scale. • Demand unbalance. • Average trip length. – Build scenarios and construct an O/D matrix for each one. – Optimize scenarios defining the optimal set of lines for each one.
  40. 40. Express Services: Main Conclusions • Allow increasing the capacity of the system • Significantly reduces social costs • Few services bring most of the benefits • Limited stop services are more promising in these situations: – The longer the average trip length – High demand – High stop density – Demand is mostly concentrated into a few O/D pairs
  41. 41. Fast Reliable Metro Attributes Actions ComfortLow waits Increase Speed Regular Headways Main drivers Increase Capacity Increase Frequency •Segregated ways/lanes and priority at junctions •Reduce dwell times •Fare payment off-bus •Buses with multiple doors •Increase distance between stations •Express services •Traffic signal priority and priority at intersectons
  42. 42. Anticipated Green Light for Buses R. Fernández
  43. 43. • Move pedestrian crossing • “Do not block” Protection of Buses on Right Turns P. Furth
  44. 44. • Move pedestrian crossing • “Do not block” • Exclusive phase for pedestrian P. Furth Protection of Buses on Right Turns
  45. 45. Metro Attributes Actions Increase Speed Regular Headways Main drivers Increase Capacity Increase Frequency •Segregated ways/lanes •Reduce dwell times •Fare payment off-bus •Buses with multiple doors •Increase distance between stations •Express services •Traffic signal priority and priority at intersectons •Improved headway control Fast ComfortLow waits Reliable
  46. 46. Santiago, Chile
  47. 47. Time-space trajectories Line 201, March 25th, 2009 0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 0 2.5 5 7.5 10 12.5 15 17.5 20 22.5 25 27.5 30 32.5 35 Tiempo (minutos) Posición(Km.) 6:30 AM 8:30 AM
  48. 48. Boston, MA; line 1 during winter
  49. 49. Boston, MA; line 1 during summer
  50. 50. Is keeping regular headways that difficult? Transit Leaders Roundtable MIT, June 2011
  51. 51. Ricardo Giesen © Bus Bus Stop Stop Waiting Passengers Waiting Passengers Bus Operations without Control
  52. 52. Ricardo Giesen © BusBusStop Stop a small perturbation… Waiting Passengers Waiting Passengers Bus Operations without Control
  53. 53. Ricardo Giesen © Bus Bus Stop Stop While one bus is still loading passengers the other bus already left its last stop Bus Operations without Control
  54. 54. Ricardo Giesen © Bus BusStop Stop Bus Operations without Control
  55. 55. Ricardo Giesen © Bus Bus Stop Stop Without bus control, bus bunching occurs!!! Bus Operations without Control
  56. 56. Stable versus unstable equilibrium
  57. 57. Stable versus unstable equilibrium
  58. 58. Stable versus unstable equilibrium
  59. 59. Stable versus unstable equilibrium
  60. 60. Stable versus unstable equilibrium
  61. 61. Stable versus unstable equilibrium
  62. 62. + - + - + - +
  63. 63. + - + - + - +
  64. 64. + - + - + - +
  65. 65. + - + - + - + And so on so forth. Our challenge is to keep an inherently unstable system: buses evenly spaced Now, if we want to prevent bunching from occurring … when is the right time to intervene?
  66. 66. Bus bunching is specially serious, where bus capacity is an active constraint.
  67. 67. Bus bunching  Severe problem if not controlled  Most passengers wait longer than they should for crowded buses  Reduces reliability affecting passengers and operators  Affects Cycle time and capacity  Creates frictions between buses (safety)  Put pressure in the authority for more buses Contribution: Control Mechanism to Avoid Bus Bunching based on real-time GPS data
  68. 68. 2. Research  Propose a headway control mechanism for a high frequency & capacity- constrained corridor.  Consider a single control strategies: Holding  Based on real-time information (or estimations) about Bus position, Bus loads and # of Passengers waiting at each stop  We run a rolling-horizon optimization model each time a bus reaches a stop or every certain amount of time (e.g. 2 minutes)  The model minimizes: Time waiting for first bus + time waiting for subsequent buses + time held
  69. 69. No control Spontaneous evolution of the system. Buses dispatched from terminal as soon as they arrive or until the design headway is reached. No other control action is taken along the route. Threshold control Myopic rule of regularization of headways between buses at every stop. A bus can be held at every stop to reach a minimum headway with the previous bus. Holding (HRT) Solve the rolling horizon optimization model not including green extension or boarding limits. Estrategias de control simuladas 3. Experiment: Control strategies
  70. 70. 4. Results: Simulation Animation Simulation includes events randomness 2 hours of bus operation. 15 minutes “warm-up” period.
  71. 71. No HRT control Wfirst 4552.10 805.33 Std. Dev. 459.78 187.28 % reduction -82.31 Wextra 1107.37 97.49 Std. Dev. 577.01 122.59 % reduction -91.20 Win-veh 270.57 1649.28 Std. Dev. 36.00 129.56 % reduction 509.57 Tot 5930.03 2552.10 Std. Dev. 863.80 390.01 % reduction -56.96 Results: Time savings
  72. 72. Results:Time-space trajectories 0 20 40 60 80 100 120 0 1 2 3 4 5 6 7 8 9 10 s2 NETS sc corrida17 Distance(Km) Time(minutes) HRT 0 20 40 60 80 100 120 0 1 2 3 4 5 6 7 8 9 10 Scenario 1 threshold run17 Distance(Km) Time(minutes) No Control This impacts comfort, reliability for users and for operators
  73. 73. Results: Bus Loads 0 5 10 15 20 25 30 0 20 40 60 80 100 120 Scenario 1 HBLRT alpha=05 Beta=05 Load(Pax.) Stop HRT 0 5 10 15 20 25 30 0 20 40 60 80 100 120 Scenario 1 HBLRT alpha=05 Beta=05 Load(Pax.) Stop No Control
  74. 74. Results: Cycle Time 25 30 35 40 45 0 50 100 150 200 250 300 350 mean =33.64 Std.Dev. =3.51 No control Frequency Cycle Time (Minutes) 25 30 35 40 45 0 50 100 150 200 250 300 350 mean =32.11 Std.Dev. =1.2 HRT 05 Frequency Cycle Time (Minutes) HRTNo Control
  75. 75. Results: Waiting time Distribution % of passengers that have to wait between: Period 15-25 Period 25-120 0-2 min 2-4 min > 4 min 0-2 min 2-4 min > 4 min No Control 57.76 29.60 12.64 63.46 27.68 8.86 HRT 79.24 20.29 0.47 87.30 12.62 0.08
  76. 76. Disobeying Drivers Similar disobedience across all drivers A subset of drivers never obey Technological Disruption Random signal fail Failure in the signal receptor equipment Signal-less zone Homogeneous distribution across buses Concentration in certain buses Concentration in certain stops 5. Impact of implementation failures
  77. 77. Impact of implementation failures
  78. 78. Common disobedience rate across drivers 8000 9000 10000 11000 12000 13000 14000 15000 0%10%20%30%40%50%60%70%80%90%100% TotalWaitingTime[Min] Obedience rate HRT, Beta=0,5 Sin Control
  79. 79. Full disobedience of a set of drivers 8000 9000 10000 11000 12000 13000 14000 15000 16000 0 1 2 3 4 5 6 7 TotalWaitingTime[Min] Deaf Buses from a total of 15 buses
  80. 80. 6. Implementation • The tool has been tested through two pilot plans in buses of line 210 of SuBus from Transantiago (Santiago, Chile) along its full path from 7:00 to 9:30 AM. • We chose 24 out of 130 stops to hold buses • One person in each of these 24 stops received text messages (from a central computer) into their cell phones indicating when each bus should depart from the stop.
  81. 81. Plan Description
  82. 82. Implementation Real time GPS information of each bus Program optimizing dispatch times for each bus from each stop Text messages were sent automatically to each person in each of the 24 stops Buses are held according to the text message instructions (never more than one minute)
  83. 83. Control Points
  84. 84. The results were very promising even though the conditions were far from ideal
  85. 85. Main results • Transantiago computes an indicator for regularity based on intervals exceeding twice the expected headway (and for how much). $ 10.000 $ 20.000 $ 30.000 $ 40.000 $ 50.000 $ 60.000 $ 70.000 $ 80.000 $ 90.000 $ 100.000 $ 110.000 Multas($CLP)
  86. 86. Main results: cycle times 2:24:00 2:31:12 2:38:24 2:45:36 2:52:48 3:00:00 3:07:12 3:14:24 3:21:36 3:28:48 3:36:00 5:52:48 6:00:00 6:07:12 6:14:24 6:21:36 6:28:48 6:36:00 6:43:12 6:50:24 6:57:36 Cycletime Dispatch time Piloto 1 Prueba10 Prueba12 Prueba13 Prueba15 Prueba16 Prueba17  No significant differences for cycle times
  87. 87. • Line 210 captured an extra 20% demand! 94.000 96.000 98.000 100.000 102.000 104.000 106.000 7.400 7.600 7.800 8.000 8.200 8.400 8.600 8.800 Demand for Line 210 (pax) Demand on All lines (pax) Unexpected result
  88. 88. 7. Conclusions Developed a tool for headway control using Holding in real time reaching simulation-based time savings of 60% Huge improvements in comfort and reliability The tool is fast enough for real time applications. Two pilot plans have shown significant improvements in headway regularity. During 2013 we will build a prototype to communicate directly to each driver.
  89. 89. Other activities • Three chilean operators will test our tool this year • Raised interest from operators in Cali and Istanbul • A research and development team is consolidating • Pedagogic tool to teach bus headway control
  90. 90. Future of BRT: Flexible Capacity Operations Juan Carlos Muñoz and Ricardo Giesen Bus Rapid Transit Centre of Excellence Pontificia Universidad Católica de Chile July 12, 2013

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