public-transport automated timetables using even … · public-transport automated timetables using...
TRANSCRIPT
Public-Transport Automated Timetables Using
Even Headways and Even Loads Concepts
32nd ATRF 2009, Auckland, NZ, 1st October 2009
Avishai (Avi ) Ceder
University of Auckland, NZ
Email:
Time = $
Great moments
in science:
Einstein discovers that time is actually money
Outline
Current Practice
Alternative Timetables
Evenly Spaced Headway
Even Loads at Max-Load Stop
Even Load at Individual Max-Load Stop
Example from L.A
Land use characteristics
Authority Constraints
Passenger demand by time of day, day-of-week
Service standards
Comparison Measures
Interlining, Dead-Heading and Shifting Departure Times Criteria
Crew List
Cost elements and Operator’s constraints
Crew Work and Rotation Rules and Constraints
Relief Points
Determination of Interchanges and
Terminals
Design of Network of Routes and Stops
Settings Frequencies and Timetables
Interchanges and
Terminals
Vehicles Scheduling
Fixed Routes and
Stops
Trip Departure Times
and Public
Timetables
Vehicle Schedules
Crew Schedules and
Duty Rosters
Crew Scheduling and Rosters
Travel Times (service and deadheading)
1
2
3
4
INPUT
INPUT COMPONENT OUTPUT
1. Running times are established for each route
2. The calculated bus speeds are examined (to
correct special cases of speeding-up and slowing-
down)
3. Headways are determined at the peak point
4. Initial departure times are set at the peak point
5. Departure times are set at all route time points
6. The departure times are adjusted at the peak
point (to include practical elements)
7. The final route Timetable is completed
8. Updating and transfer to marketing
Current Practice
LA Metro files include 40,000 trips. The data
is collected manually and then key punched
About 40% of the scheduler’s time is devoted
to data entry and proofreading generated
reports
Current Practice Example:
“A stitch in time would have confused Einstein”.
… many stitches in public-transport (PT) timetables
would confuse the passengers.
PT timetable is one of the predominant bridges
between the operator (and/or the community) and the
passengers.
More attention should be provided for the
construction of PT timetable in order to improve its
correspondence with the fluctuated passenger
demand.
Importance of PT Timetables
Public-Transport (PT) timetable is perhaps the main
reference for defining unreliable transit service.
The assumption that passengers will adjust
themselves to given timetables (with headways of, say,
longer that 10 minutes) instead of adjusting the
timetables to the passenger demand is one of the
largest sources of unreliable service.
When passenger demand is not met, the PT vehicles
are slowing down (increased dwell time), behind the
schedule and entering the inevitable process of further
slow down.
Scope
1. Evaluate alternative timetables in terms of required resources
2. Improve the correspondence of vehicle departure time with passenger demand while minimizing resources
3. Improve timetables for synchronization
4. To permit in timetable construction procedure, direct bus frequency changes for possible exceptions (known to the scheduler) which do not rely on passenger demand data
5. To allow the construction of timetables with headway smoothing techniques (similar to that performed manually) in the transition segments between adjacent time periods
6. Integrate different headway setting and different timetables construction methods
Objectives
Wish to
attain
Alternative Timetables
Even headway
Max load (point
check) methods
Load profile (ride
check) methods
Intuitive or experience-
based determination
Daily Max load
(Method 1)Hourly Max Load
(Method 2)
With level-of-service
criterion (Method 4)
Predetermined number of departuresClock headways
Without level-of-service
criterion (Method 3)
Even average load
Method for
Setting
Frequencies
Special Requests
At individual vehicle
Max load point
At hourly Max load
point
Type of
Timetable
Public Timetable(list of departure times per timepoint)
Three Procedures
Example for the Three Procedures
Two basic assumptions: (a) the average load observed is a representative
value of the actual demand and it is independent of the exact setting of
departure times; (b) the passengers observed on-board are accumulated
at a uniform rate.
Evenly Spaced Headways with
a Smoothing Technique
Even Average Load at the Max Load Stop
How to
fix the
uneven
loads ?
Data given on
individual vehicles
average loads (at
Max-Load stop)
Even Average Load on Individual Veh Max-Load Stops
Comparing the Three Procedures
Parameter file
Headway switch “1” = Even headways
“2” = Even-load headways
Frequency Method
(for Each operating
option) first period in which
the option is operated
last period
method used to determine
frequency
Clock headway switch “1” = clock headways
“0” = otherwise
Specified departures specified number of daily trips
“0” if not specified
SCRTD line 217
Real-Life Example (bus line 217 in LA)
Load(# of
Passengers)
Distance
(km)
Line 217 Morning-Peak Load Profile
Line 217 Afternoon-Peak Load Profile
Load(# of
Passengers)
Distance
(km)
Line 217 (South)
0
2
4
6
8
10
12
5 7 9 11 13 15 17 19 21 23
Time of day
Fre
qu
ency
(#
of
veh
icle
s) Observed Method 2
Method 3 Method 4 (20%)
Line 217 (North)
0
2
4
6
8
10
12
5 7 9 11 13 15 17 19 21 23
Time of day
Fre
qu
en
cy (
# o
f v
ehic
les) Observed Method 2
Method 3 Method 4 (20%)
Computer Generated Timetable of line 217 at the Fairfax/Rosewood Stop
Min single
route
required
fleet size=15
Min fleet size =
largest number
of buses
departing in any
time interval
of length T
T= round trip
time including
layover and
turn around
time
Computer Generated Timetable of Line 217at the Fairfax/Rosewood Stop
Computer Generated Timetable of Line 217at the Fairfax/Rosewood Stop
Computer Generated Timetable of Line 217
at the Fairfax/Rosewood Stop
Computer Generated Timetable of Line 217across all Stops
Nine-tenth of
wisdom
is being wise
in time
(Roosevelt)
End of Presentation
Thank You!
Public-Transport Automated Timetables Using
Even Headways and Even Loads Concepts
32nd ATRF 2009, Auckland, NZ, 1st October 2009