MATSim’s Volume-Delay Relationship?
relation to BPR function?
tt
?
use deqsim Charypar?
1
Context:
A Glimpse at Emergence in Agent-Based
Simulations
A. Horni and L. Montini, IVT, ETH Zürich
ApplauSim (A Simulation of Synchronous Applause)
MATSim
Motivation for Emergence Discussion
“phantom traffic jams”
Chowdhury et al.
(2000)
“one of the most seductive buzzwords of complexity science”
MacKay (2008, p.T274)
“when constructing agent systems, you should regard emergence as
an important concept” … “you can try to “design in” the emergence
that you want”. Odell (1998)
Emergence and Non-Linearity
Superposition principle invalid
-> non-linear regimes
First investigation: functional form of MATSim network load simulation
4
Flow-Density and Travel Time
Diss Charypar
deqsim
flow
density
tt
?
?
demand
5
Flow-Density and Travel Time
flow
Diss Charypar
deqsim
density
flow
relation to BPR function
for traffic assignment:
b usually between 5 and 11
tt
6
Evaluation of MATSim Network Load Simulation
standard mobsim
(qsim) with or without param
trafficDynamics =withHolesExperimental
removeStuckVehicles
7
8
BPR
MATSim
standard mobsim
storageCapacityFactor = 10.0
storageCapacityFactor = 1.0 -> log-like fcn
storageCapacityFactor = flowCapacityFactor ->
log-like fcn
9
BPR
MATSim
standard mobsim
storageCapacityFactor = 10.0
storageCapacityFactor = 1.0
storageCapacityFactor = flowCapacityFactor
10
Increase storage capacity
flow
density
tt
?
demand
No backtraveling gaps: Nurhan Sim
flow
density
tt
?
demand
And Now?
• reproduce experiments
• back-traveling gaps (repeat experiment with deqsim)
• var(v) on links -> phantom traffic jams
• agent interactions in large networks & feedback -> non-linear in nature
(Goldstein 1999)
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