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8/14/2019 Microsimulation Presentation
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An introduction to microsimulation
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An introduction to microsimulation
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An introduction to microsimulation
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Limitations of traffic models
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What does microsimulation deliver ?
Provides the means to fully test the likely traffic flow
responses to proposed network changes at a detailedlevel
Helps transport planners to design road networks, traffic
management schemes and UTC systems
Outputs 3D visual graphics as well as detailednumerical data
Allows variation in traffic flows and conditions to be
accounted for in assessments by undertaking and
analysing multiple model runs
Allows operational and economic assessments of
scheme options and comparison with reference network
to be undertaken
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How does microsimulation work?
o It works in the same way thatroad users think
o Applies simple rules :
speed / car following
lane changing
gap acceptance
driver behaviour
route choice
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How does microsimulation work?
Drivers behave d if ferent ly
To reflect this, microsimulation
assigns parameters which influence:
Speed and overtaking
Gaps to move into
When to be in the right lane
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How does microsimulation work?
Speed :
What speed do I
wantto do?
What speed canI
do?
What speed mus tI
do?
Do I maintain my
speed, accelerate or
decelerate?
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How does microsimulation work?
Lane Changing :
What lanes can I use now?
What lane do I need to be in
soon?
Do I need to change lane?
Can I change lane?
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How does microsimulation work?
Considerat ion of other vehic les:
Car following : Am I too
close?
Lane behaviour : Should I
slow to let someone else
manoeuvre?
Gap acceptance : Can I move
out now?
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How does microsimulation work?
Signals:
To model wide area urban traffic flow
in congested networks it is essential to
include control systems in the
simulation
In simple networks this might just
require the inclusion of fixed time
signals
In complex networks, because driversreact to changing conditions, signal
optimisation and UTC systems can be
included.
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How does microsimulation work?
Vehicle routeing :
Major and minor routes
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How does microsimulation work?
Vehicle routeing :
Find the quickest way
Some drivers will avoid
congestion, but others may not
Waypoints for longer journeys
Route choice advice from ITS
Public transport fixed routes
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How does microsimulation work?
Vehicle routeing :
Waypoints
strategic and local networks in one model
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How does microsimulation work?
Organised chaos :
Cause and effect is an
important feature of
congested road networks.
Only microsimulation can
model this.
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How does microsimulation work?
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Microsimulation model inputs
Hardly d i f fer f rom other model l ing
system inputs :
Principal difference is thedependence on data in smaller
time intervals
The source of trip demand data is
common to all traffic flow models
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Microsimulation model inputs
Hardly d i f fer f rom other model l ing
system inputs :
The development of trip demandmatrices is crucial for any form of
modelling
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What does microsimulation deliver ?
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What does microsimulation deliver ?
Fuzzy model l ing = Statist ical
est imates of o utputs
ie. no single num ber answ ers
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What does microsimulation deliver ?
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What does microsimulation deliver ?
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What does microsimulation deliver ?
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What does microsimulation deliver ?
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What does microsimulation deliver ?
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What does microsimulation deliver ?
1. A platoon builds up behind
a lorry (yellow arrow)
heading north on the A77
from Stranraer.
2. The platoon approaches
the WS2+1 section. The
second blue car anticipates
overtaking.
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What does microsimulation deliver ?
3. The second blue car is the
first to overtake.
4. The blue car clears the
head of the platoon.
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What does microsimulation deliver ?
5. Meanwhile, the maroon
Mercedes (arrowed white in
Fig.1) has also overtaken.
This is the driver's view.
6. The blue car reaches the
end of the overtaking
section.
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What does microsimulation deliver ?
7. The blue and maroon cars
speed away from the head
of the platoon, enjoying the
downstream time benefit.
8. The rest of the platoon exits
the overtaking section,
heading north to the
next one.
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What does microsimulation deliver ?
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What does microsimulation deliver ?
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