This document discusses bus headway variability and strategies to achieve regular bus service. It begins by outlining what passengers seek in public transit and how to achieve those attributes. While increasing speed and fleet can help, it is important to also focus on decreasing travel time variability and achieving regular headways for reliability. The impacts of unreliable service with bus bunching are then reviewed, including increased waiting times, occupancy and user dissatisfaction. Finally, the document discusses that solutions do exist, such as dedicated infrastructure, signal priority and real-time control systems, to stabilize service and achieve the goal of reliable transit.
HARDNESS, FRACTURE TOUGHNESS AND STRENGTH OF CERAMICS
Full cost reliability by Juan Carlos Muñoz
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
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. What do people seek when travelling
in public transport?
Fast Low waits Comfortable Reliable
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. To achieve these attributes….
Fast Low waits Comfortable Reliable
INCREASE SPEED!
AND THEN MAYBE IF WE
HAVE SPARE TIME FOCUS
ON REGULAR HEADWAYS….
11. 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 !
12. 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
17. Today we will address three questions
Why does bus bunching happen?
What are the impacts?
1
2
Does it have a solution?3
18. Why does bus bunching happen?
• Dispatch strategy
• Speed variability
• Travel time variability
• Dwell time variability
19. Why does bus bunching happen?
Time (minutes)
Position (km)
20. Why does bus bunching happen?
• Dispatch strategy
• Speed variability
• Travel time variability
• Dwell time variability
21. Why does bus bunching happen?
Congestion Traffic lights Driver heterogeneity
Travel time variability
22. Why does bus bunching happen?
Stochastic passenger arrivals
at each stop
Dwell time variability
23. Today we will address three questions
Why does bus bunching happen?
What are the impacts?
1
2
Does it have a solution?3
24. What are the impacts?
Impacts are various, affecting:
Users Operators
25. What are the impacts?
• Consider the following bus service
• 5 min average headway
• 80-pax capacity buses
• An average demand of 50 pax/bus
26. What are the impacts?
8:00 8:05 8:10 8:15 8:20
8:00 8:02 8:10 8:12 8:20
27. 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
28. 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
29. 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
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
31. 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?
32. What are the impacts?
User
Satisfaction
Occupancy per bus
33. 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.
34. 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
35. 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
36. 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
37. 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
38.
39. 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 !
40. Today we will address three questions
Why does bus bunching happen?
What are the impacts?
1
2
Does it have a solution?3
41. Does it have a solution?
•Yes!
• Dedicated infrastructure
• Transit signal priority
• Real-time control at dispatching
and along the route
• (developed by )
46. 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
47. 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
48. Does it have a solution?
Ok! Hold Go faster
(if possible)
Slow down
50. The future of BRT should be written with double R
BRRT
Bus Rapid and Reliable Transit
51. 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