complexity science & transport systems jeffrey johnson & joan serras design, development,...
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Complexity Science & Transport Systems
Jeffrey Johnson & Joan SerrasDesign, Development, Environment & Materials
The Open University
to infinity … and beyond
The Complex Systems Perspective:
Road systems - interconnected systems of dynamic systems.
Many subsystems: Populations, roads, railways, land uses, regulations. All have multilevel structure, e.g. people, families, neighbourhoods, cities. All have dynamics => emergent dynamics of whole
Subsystems have thousands or millions of partscan only be modelled on computers.
How to represent and modelling huge heterogeneous multilevel road systems such as the whole of the UK or Europe ?
Traffic Modelling Conference 31-March-2009 Open University
Everything is becoming more & more connected
Milton Keynes
Bedford
Traffic Modelling Conference 31-March-2009 Open University
Everything is becoming more & more connected
Milton Keynes
Bedford
Traffic Modelling Conference 31-March-2009 Open University
Everything is becoming more & more connected
Milton Keynes
Bedford
Traffic Modelling Conference 31-March-2009 Open University
Everything is becoming more & more connected
Milton Keynes
Bedford
Cannot divide & rule
- the are connected !
Traffic Modelling Conference 31-March-2009 Open University
Objectives of the research
To model road system in an holistic way such that:
• captures the dynamics of road traffic:
microdynamics: e.g. shock wavesmacrodynamics: e.g. transmission of congestion
Traffic Modelling Conference 31-March-2009 Open University
Objectives of the research
To model road system in an holistic way such that:
• captures the dynamics of road traffic:
microdynamics: e.g. shock wavesmacrodynamics: e.g. transmission of congestion
• includes all the smallest level links – nothing left out!
• aggregates bottom-up dynamics – no information loss!
Traffic Modelling Conference 31-March-2009 Open University
Objectives of the research
To model road system in an holistic way such that:
• captures the dynamics of road traffic:
microdynamics: e.g. shock wavesmacrodynamics: e.g. transmission of congestion
• includes all the smallest level links – nothing left out!
• aggregates bottom-up dynamics – no information loss!
• distributes computation and data naturally across administrative levels
Traffic Modelling Conference 31-March-2009 Open University
Objectives of the research
To model road system in an holistic way such that:
• captures the dynamics of road traffic:
microdynamics: e.g. shock wavesmacrodynamics: e.g. transmission of congestion
• includes all the smallest level links – nothing left out!
• aggregates bottom-up dynamics – no information loss!
• distributes computation and data naturally across administrative levels
• illustrate by huge road systems, e.g. London, Europe
Traffic Modelling Conference 31-March-2009 Open University
Starting point: it is like this
Plots of land – ‘zones’
Traffic Modelling Conference 31-March-2009 Open University
Starting point: it is like this
Plots of land – ‘zones’
Activity Land Uses
Traffic Modelling Conference 31-March-2009 Open University
Starting point: it is like this
Plots of land – ‘zones’
Activity Land Uses
Traffic Modelling Conference 31-March-2009 Open University
Starting point: it is like this
origin
destination
Trips are made between located activities
Traffic Modelling Conference 31-March-2009 Open University
Starting point: it is like this
origin
destination
Traffic Modelling Conference 31-March-2009 Open University
Starting point: it is like this
origin
destination
Traffic Modelling Conference 31-March-2009 Open University
Starting point: it is like this
origin
destination
Traffic Modelling Conference 31-March-2009 Open University
Starting point: it is like this
origin
destination
Traffic Modelling Conference 31-March-2009 Open University
Starting point: it is like this
origin
destination
Traffic Modelling Conference 31-March-2009 Open University
Starting point: it is like this
origin
destination
A route traverses a set of zones at different ‘levels’
Traffic Modelling Conference 31-March-2009 Open University
Starting point: it is like this
Plots aggregate into larger areas – zones
Traffic Modelling Conference 31-March-2009 Open University
Larger zones aggregate into even larger zones
Traffic Modelling Conference 31-March-2009 Open University
Larger zones aggregate into even larger zones
Traffic Modelling Conference 31-March-2009 Open University
Larger zones aggregate into even larger zones
Traffic Modelling Conference 31-March-2009 Open University
Even larger zones aggregate into even larger zones
Traffic Modelling Conference 31-March-2009 Open University
Even larger zones aggregate into even larger zones
Traffic Modelling Conference 31-March-2009 Open University
… and so on to zones for London, England, Europe, …
Traffic Modelling Conference 31-March-2009 Open University
We assume there is a hierarchical set of zones
ZN-3 … ZN-1 ZN ZN+2 … ZN+k-1 ZN+k
Traffic Modelling Conference 31-March-2009 Open University
We assume there is a hierarchical set of zones
link between junction nodes
kitchen
house plot, road segment
ZN-3 … ZN-1 ZN ZN+2 … ZN+k-1 ZN+k
Traffic Modelling Conference 31-March-2009 Open University
We assume there is a hierarchical set of zones
link between junction nodes
kitchen
house plot, road segment
ZN-3 … ZN-1 ZN ZN+2 … ZN+k-1 ZN+k
Abstract higher level lines (to be explained)
Traffic Modelling Conference 31-March-2009 Open University
Define a set of nodes -
where a vehicle can cross a road zone boundary
Traffic Modelling Conference 31-March-2009 Open University
Define a set of nodes -
where a vehicle can cross a road zone boundary
A link is defined by a pair of nodes
Traffic Modelling Conference 31-March-2009 Open University
Define a set of nodes -
where a vehicle can cross a road zone boundary
A link is defined by a pair of nodes
‘conventional’ links exist at Level N
Traffic Modelling Conference 31-March-2009 Open University
A
B
A Level-N route is a set of Level N links
Traffic Modelling Conference 31-March-2009 Open University
A
B
There are many N-Level routes between A and B
Traffic Modelling Conference 31-March-2009 Open University
A
B
There are many N-Level routes between A and B
Traffic Modelling Conference 31-March-2009 Open University
A
B
There are many N-Level routes between A and B
Traffic Modelling Conference 31-March-2009 Open University
A
B
Let this set of routes be a Level N+2 Link
Traffic Modelling Conference 31-March-2009 Open University
There are ~8000 Level-N routes between A and B
AB
~ 20 routes ~ 20 routes ~ 20 routes
Traffic Modelling Conference 31-March-2009 Open University
Put a N+2-level nodes on the boundaries
AB
Traffic Modelling Conference 31-March-2009 Open University
Make Level N+2 links and a Level N+2 route
AB
Traffic Modelling Conference 31-March-2009 Open University
Make Level N+2 links and a Level N+2 route
AB
Traffic Modelling Conference 31-March-2009 Open University
Make Level N+2 links and a Level N+2 route
AB
Traffic Modelling Conference 31-March-2009 Open University
We now have 20 + 20 + 20 + 1 = 61 << 8000 routes !
AB
~ 20 routes ~ 20 routes ~ 20 routes
Traffic Modelling Conference 31-March-2009 Open University
We now have ~ 100,000 possible routes !
AB
~ 50 routes ~ 50 routes ~ 50 routes
Traffic Modelling Conference 31-March-2009 Open University
We now have ~150 + 9 = ~159 <<< 100,000 routes!
AB
~ 50 routes ~ 50 routes ~ 50 routes
Traffic Modelling Conference 31-March-2009 Open University
If the routes cross a Level N+3 Zone ..
AB
Traffic Modelling Conference 31-March-2009 Open University
AB
… make a Level N+3 link as the set of N+2 routes
Traffic Modelling Conference 31-March-2009 Open University
AB
Hierarchical routes used for routing trips
Level N+2 links
Level N+1 linksLevel N+1
Level N links
Level N links
Within hierarchical zones, always use the highest level links available
Traffic Modelling Conference 31-March-2009 Open University
AB
Higher level links have lower variance !
Level N+2 links
Level N+1 linksLevel N+1
Level N links
Level N links
rela
tive
fr
equ
ency
travel time, minutes travel time travel time, hours
100%
rela
tive
fr
equ
ency
rela
tive
fr
equ
ency
Traffic Modelling Conference 31-March-2009 Open University
AB
Hierarchical routes used for routing trips
Level N+2 links
Level N+1 linksLevel N+1
Level N links
Level N links
Note: higher level links have more stable flow and travel time statistics than lower level links initialisation heuristics ?
Traffic Modelling Conference 31-March-2009 Open University
TRANSIMS – from Micro simulation to Macro dynamics
Traffic Modelling Conference 31-March-2009 Open University
TRANSIMS – from Micro simulation to Macro dynamics
Traffic Modelling Conference 31-March-2009 Open University
TRANSIMS – from Micro simulation to Macro dynamics
Traffic Modelling Conference 31-March-2009 Open University
TRANSIMS – from Micro simulation to Macro dynamics
Traffic Modelling Conference 31-March-2009 Open University
TRANSIMS – from Micro simulation to Macro dynamics
Traffic Modelling Conference 31-March-2009 Open University
Level N+7
Level N+6
Level N+5
Level N+4
Level N+3
Level N+2
Level N+1
Level N
Level N-1
Level N-2
Level N-3
The World !
Region (e.g. the Americas, Asia )
Nation (e.g. USA, UK )
State (e.g. Virginia, Buckinghamshire)
City, rural region (e.g. New River Valley)
Small town (e.g. Blacksburg, Milton Keynes)
Neighbourhood (e.g. VT Campus)
Conventional Links and zones
Road segment, plot of land
House, garden, garage
Rooms
Traffic Modelling Conference 31-March-2009 Open University
Research in Progress
1.Devise new microlevel simulation
2. Implement at microlevel for Milton Keynes
3. Implement hierarchical routing schemes
4.New synthetic micropopulation – all properties
5. Run the system for Milton Keynes
6. … extend to UK
7. … extend to Europe
8. … extend to infinity, and beyond !