Question

write the simulation algorithm for Two lane one way traffic condition.(explain along with a flow chart).

Answer 1

Vehicle
Capacity
(Number of
passengers)
Load Factor
(Peak Period)
Service
Frequency
(Number of
vehicles per
hour per
stopping bay)
Number of
stopping bays
per station
Capacity Flow
(Number of
passengers per
hour per
direction)
70 0.85 20 1 1,190
160 0.85 20 1 2,720
270 0.85 20 1 4,590
70 0.85 30 1 1,785
160 0.85 30 1 4,080
270 0.85 30 1 6,885
70 0.85 60 1 3,570
160 0.85 60 1 8,160
270 0.85 60 1 13,770
70 0.85 20 2 2,380
160 0.85 20 2 5,440
270 0.85 20 2 9,180
70 0.85 30 2 3,570
160 0.85 30 2 8,160
270 0.85 30 2 13,770
70 0.85 60 2 7,140
160 0.85 60 2 16,320
270 0.85 60 2 27,540
70 0.85 20 4 4,760
160 0.85 20 4 10,880
270 0.85 20 4 18,360
70 0.85 30 4 7,140
160 0.85 30 4 16,320
270 0.85 30 4 27,540
70 0.85 60 4 28,560
160 0.85 60 4 32,640
270 0.85 60 4 55,080

Factor Typical Range
Vehicle capacity for standard-size buses 60-75 passengers
Vehicle capacity for articulated buses 140-170 passengers
Vehicle capacity for bi-articulated buses 240-270 passengers
Load factor for peak period 0.80 – 0.90
Load factor for off-peak period 0.65 – 0.80
Service frequency per stopping bay for peak period 20 – 60 buses per hour
Service frequency per stopping bay for off-peak
period
7 – 15 buses per hour
Dwell time for peak period 20 – 40 seconds
Dwell time for off-peak period 17 – 30 seconds
Number of stopping bays 1 – 5 stopping bays
Source: (22)
Bogota’s Transmilenio BRT system currently transports an average actual peak period
capacity of 45,000 pphpd – the largest BRT system capacity known to exist. Many BRT
and busway systems in Brazil such as in Sao Paolo, Porto Alegre, Belo Horizonte, and
Curitiba – are capable of achieving peak period capacities ranging between 20,000 pphpd
and 35,000 pphpd. In the case of Bogota, its capacity is attained mainly through the
following factors:
• Use of articulated buses with a capacity of 160 passengers
• Stations with multiple stopping bays that can accommodate up to five buses
per direction simultaneously
• Passing lanes at BRT stations to permit express and limited-stop vehicles to
pass local bus services
• Multiple combinations of routing options that include local, limited-stop, and
express services
• Average service frequency per route of 20 buses per hour and a service
frequency as high as 60 buses per hour during peak periods
• Station dwell times of approximately 20 seconds that are achieved by means
of the following attributes:
o At-level boarding and alighting
o Pre-board or off-line fare collection and fare verification
o Multiple sets of large double doors on each side of the BRT vehicle
Systems such as in Quito (Ecuador) have only a single lane in each direction and can
reach hourly capacities per direction of approximately 14,000 (Table 1-3). However,
while the Porto Alegre Assis Busway in Brazil has only one lane in each direction, it has
achieved an hourly capacity of 28,000 per direction because it utilizes multiple stopping tual Bus Rapid Transit Corridor Capacities: Number of Passengers per Hour
per Direction
BRT Corridor
Location
Achievable Capacity
or
Actual Measured
Peak Flow
(passengers per hour
per direction)
Average Speed
(km/h)
Average Peak
Service
Frequency
(number of
buses per hour)
SOUTH AMERICA
Bogota Transmilenio 45,000 27 20
Santiago
Transantiago
37,000 20 20
Sao Paolo – 9 de
Julho Busway
34,910 22 120
Porto Alegre Assis
Brazil Busway
28,000 15 120
Belo Horizonte
Christiano Machado
21,100 27.4 314
Curitiba 20,000 19 30
Goiania (Brazil) 11,500 18 90
Quito Trolebus 9,600 15 60
Pereira (Columbia)
Megabus
6,900 20 12-20
Quito Ecovia 6,400 18 30
Quito Central Norte 6,400 23 30
Guayaquil (Equador) 5,400 22 24
CENTRAL AMERICA
Guatemala City –
TransMetro
5,000 25 N/A
NORTH AMERICA
Ottawa – Transitway 10,000 38.7 30
Mexico City
Metrobus
8,500 19 57
Pittsburgh East
Busway
5,000 40.1 15
Leon (Mexico)
Optibus
2,900 18 9-24
Pittsburgh South
Busway
1,650 34.5 30
Vancouver 99 BLine
1,700 23 15
Pittsburgh West
Busway
1,365 40.5 12
Bosto

n Silver Line 1,260 12.8 12-20

3.1 Mathematical Modeling
The objective is to minimize the weighted sum of the dwell time and travel time for all
BRT trips: ,
where equals the weight for the dwell time of trip i, and is the weight for the
travel time of trip i. The different weights provide the ability to prioritize the trade-off
between minimizing travel time and minimizing dwell time. For example, if reducing the
dwell time is more important in a BRT system, a larger can be applied.
Constraints on the travel speed:
The travel speed needs to be between the given range for the inbound and outbound buses.Constraints on the dwell time:
The dwell time at a bus stop needs to be between the minimum and maximum allowed
dwell times: .
For express BRT buses, the departure time equals the arrival time if a bus stop is not
scheduled to service the stop: .
Constraints on the synchronization between the buses running in the same direction
In the single-track train problem, more than one train traveling in the same direction can
remain in the station. The capacity of a station is generally not a restriction. Nevertheless,
the capacity of a bus stop is limited. In general, only one bus can dwell at the bus stop in
the BRT system unless infrastructural improvements are made to accommodate more
than one bus at a time. Another bus has to wait until the bus currently at the bus stop
departs. The capacity of the BRT stop is an important issue in modeling the BRT system.
During operations, an express bus may pass a regular bus that departs earlier, although
the express bus cannot pass another express bus that starts earlier. A regular bus cannot
pass any other regular or express bus. Let FC(i) be the set of trips that have a potential
conflict with trip i in the same direction. For the regular trip, FC(i) includes only the trip
that departs just earlier than trip i. For the express trip, FC(i) includes all regular trips and
the express trip that departs earlier than trip i.
Constraints (1e) ensure that a regular bus cannot enter a bus stop before earlier buses
leave that bus stop. Constraints (1f) guarantee that an express bus cannot enter a bus stop
before other express buses that started earlier leave that same bus stop. Constraints (1g)
through (1l) ensure that if an express bus overtakes a regular bus, it occurs in a bus