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Full cost reliability by Juan Carlos Muñoz

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Resumen:

In recent decades, the main focus in public transport operations has been increasing its speed. Increasing speed not only allows for faster trips, but also a higher frequency with the same fleet, thus reducing waiting times and crowdedness inside the vehicles. This interest in speed has ignored a second key dimension in level of service: reliability. In this article, we provide a full range of impacts of an unreliable public transport service. We demonstrate how regularising headway could improve level of service beyond the gains of simply increasing the operational speed. Regular headways positively affect comfort, reliability, travel and wait time, operational costs, and even some urban impacts of bus services. Thus, the focus for public transport agencies and operators should be redirected to reliability. This is fundamental for making public transport an attractive travel alternative and therefore must become a core goal for urban sustainability.

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Full cost reliability by Juan Carlos Muñoz

  1. 1. The full cost of bus headway variability and our experience to achieve a regular service Juan Carlos Munoz Bus Rapid Transit Centre of Excellence Centro de Desarrollo Urbano Sustentable, CEDEUS Pontificia Universidad Católica de Chile Hong Kong, December 8th, 2018 @JuanCaMunozA
  2. 2. Work done with collaborators at PUC
  3. 3. Cities need its citizens to use public transport This is easier if citizens like their public transport, if they are satisfied with its use
  4. 4. What do people seek when travelling in public transport? Fast Low waits Comfortable Reliable
  5. 5. How can we achieve these attributes? DECREASE TRAVEL TIME INCREASE FREQUENCY INCREASE FLEET OR INCREASE SPEED INCREASE TRANSPORT CAPACITY DECREASE TRAVEL TIME VARIABILITY Fast Low waits Comfortable Reliable INCREASE SPEED INCREASE FLEET, VEHICLE SIZE OR INCREASE SPEED REGULAR HEADWAYS
  6. 6. To achieve these attributes…. Fast Low waits Comfortable Reliable INCREASE SPEED! AND THEN MAYBE IF WE HAVE SPARE TIME FOCUS ON REGULAR HEADWAYS….
  7. 7. BRT : Bus Rapid Transit
  8. 8. But… is this enough?
  9. 9. What about reliability? What are the impacts of an unreliable service?
  10. 10. To achieve these attributes… Fast Low waits Comfortable Reliable I N C R E A S E S P E E D A N D R E G U L A R H E A D W A Y S !
  11. 11. Vehicles in public transport systems behave like magnets…. Any perturbation and the equilibrium is lost… all around the world. Regular intervals is an unstable equilibrium
  12. 12. Bus bunching… observed in London
  13. 13. Bus bunching… observed in Beijing
  14. 14. Bus bunching… observed in Boston
  15. 15. Bus bunching… observed in Santiago
  16. 16. Today we will address three questions Why does bus bunching happen? What are the impacts? 1 2 Does it have a solution?3
  17. 17. Why does bus bunching happen? • Dispatch strategy • Speed variability • Travel time variability • Dwell time variability
  18. 18. Why does bus bunching happen? Time (minutes) Position (km)
  19. 19. Why does bus bunching happen? • Dispatch strategy • Speed variability • Travel time variability • Dwell time variability
  20. 20. Why does bus bunching happen? Congestion Traffic lights Driver heterogeneity Travel time variability
  21. 21. Why does bus bunching happen? Stochastic passenger arrivals at each stop Dwell time variability
  22. 22. Today we will address three questions Why does bus bunching happen? What are the impacts? 1 2 Does it have a solution?3
  23. 23. What are the impacts? Impacts are various, affecting: Users Operators
  24. 24. What are the impacts? • Consider the following bus service • 5 min average headway • 80-pax capacity buses • An average demand of 50 pax/bus
  25. 25. What are the impacts? 8:00 8:05 8:10 8:15 8:20 8:00 8:02 8:10 8:12 8:20
  26. 26. What are the impacts? • Increase in average occupancy • Longer waiting times correlate with high occupancy • More users suffer high occupancy • Increase in occupancy variability • Generates uncertainty in the level of service
  27. 27. What are the impacts? • Increase in waiting times • One minute of waiting is perceived as two or three minutes of in-vehicle time • Increase in the variability of waiting times • Leads to earlier departures for users
  28. 28. What are the impacts? • Increase in dwell times • Boarding and alighting is slow and creates friction between passengers • Increase in the variability of dwell time • Damages the reliability of the service • Operators need extra fleet and drivers due to variable cycle times
  29. 29. Cities need its citizens to use public transport This is easier if citizens like their public transport, if they are satisfied with its use
  30. 30. Cities need its citizens to use public transport This is easier if citizens like their public transport, if they are satisfied with its use How does reliability affect user satisfaction?
  31. 31. What are the impacts? User Satisfaction Occupancy per bus
  32. 32. What are the impacts? User Satisfaction Occupancy per bus50 pax 80% Imagine a regular service with a 5 minute interval, 50 passengers per bus and 63% occupancy.
  33. 33. What are the impacts? User Satisfaction 50 pax 80% Suppose the service is not regular, and operates with intervals of 2 and 8 minutes alternately (with occupancies of 25% and 100% respectively). 90% 20 pax 80 pax 10% Occupancy per bus
  34. 34. What are the impacts? User Satisfaction 63% 80% 90% 25% 100% Average occupancy of buses will be 63%, with an apparent satisfaction of 50%. 50% 10% Occupancy per bus
  35. 35. What are the impacts? User Satisfaction 63% 80% 90% 25% 100% Average occupancy of perceived by users will be 85%, with a satisfaction level of only 26%! 50% 85% 26% 10% Occupancy per bus
  36. 36. What are the impacts? User Satisfaction 63% 80% 90% 25% 100% 50% 85% 26% 10% This is what we planned for… This is what we achieved with no control! Occupancy per bus
  37. 37. To achieve these attributes… Fast Low waits Comfortable Reliable I N C R E A S E S P E E D A N D R E G U L A R H E A D W A Y S !
  38. 38. Today we will address three questions Why does bus bunching happen? What are the impacts? 1 2 Does it have a solution?3
  39. 39. Does it have a solution? •Yes! • Dedicated infrastructure • Transit signal priority • Real-time control at dispatching and along the route • (developed by )
  40. 40. Does it have a solution?
  41. 41. Does it have a solution? Source: mto.gov.on.ca
  42. 42. Does it have a solution? No control With control Color indicates bus load!
  43. 43. Time-space trajectories 0 20 40 60 80 100 120 0 1 2 3 4 5 6 7 8 9 10 s2 NETS sc corrida17Distance(Km) Time(minutes) Real Time Holding 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
  44. 44. 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 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 Real Time Holding
  45. 45. Cycle times 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) No Control Real Time Holding
  46. 46. Does it have a solution? Ok! Hold Go faster (if possible) Slow down
  47. 47. Does it have a solution?
  48. 48. The future of BRT should be written with double R BRRT Bus Rapid and Reliable Transit
  49. 49. The full cost of bus headway variability and our experience to achieve a regular service Juan Carlos Munoz Bus Rapid Transit Centre of Excellence Centro de Desarrollo Urbano Sustentable, CEDEUS Pontificia Universidad Católica de Chile Hong Kong, December 8th, 2018 @JuanCaMunozA

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