Post on 20-Dec-2015
Overview
Methodological approach
Key achievements
Current and future challenges
Methodological approach
Key achievements
Current and future challenges
Influences on personal travel
Fixed•Age, sex, health
Limited Choice•Employment, income, household composition, household location
Active Choice•Lifestyle (e.g. car, motorbike, cycle ownership)
Influences on travel
Where am I?
Where am I going? (should I go?)
How often? (or not at all?)
How will I get there? (what’s available?)
When can / should I go?
What route to take?
Life, the Universe and Everything
TrafficModels
Transport Models TrafficModels
Driver & VehicleBehaviour
A model
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Behaviour model
Logic based
If
Then
this situation occurs
do thisbased on my vehicle and my driving style
Driver behaviour
Condensed into just three decisions
•What lane?~Mandatory and Discretionary
•What speed?
•What gap?
What lane?
Mandatory rangers(i.e. need to be a lane or range of lanes for a manoeuvre)
•When do I find out what lane(s) I should be in?~Signposting
•If not in right lane(s), then ‘urgency’ to get in lane increases as I get closer to hazard
What lane?
Discretionary suggesters
•Keep left
•Vehicle behind me
•Slow vehicle in front of me
•Congestion
•Avoidance (incident, bus)
•On-slip / ramp
What lane?
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Lane weightings applied
•Seniority can be applied
What speed?
Acceleration suggesters – lowest value chosen
•Target speed
•Geometric
•Following
•Want lane change
•Let in
•Undertaking
•Friction
•Overtake (opposite carriageway)
•End speed
•Stop
•Yellow box
•Bus stop (for buses)
What speed?
Finally a set of vehicle specific modifiers
•Drag and inertia
•Gradient~Modifies acceleration~Modifies target speed (for GVs only)
What gap?
A Gap when driving is generally time-based
•Junctions
•Headway
•Minimum gap~This is the closest distance I’ll get to the vehicle in front of me.
Behaviour model
Logic based
If
Then
this situation occurs
do thisbased on my vehicle and my driving style
Driver characteristics
Aggression
•This determines how I behave
Awareness
•This determines how I respond to others
Default is Normal Distribution
•Apply a spread0
5
10
15
20
25
30
1 2 3 4 5 6 7 8 9
Default Distribution
Fre
qu
ency
Distribution modification
Not all distributions are normal
•Apply a skew
0
5
10
15
20
25
30
1 2 3 4 5 6 7 8 9 10 11 12 13
Skew Distribution
Fre
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ency
Vehicle characteristics
Top speed
•Physical rather than legal
Bounds of acceleration / braking
Dimensions
•Length, width, height and mass
Industry Acceptance
First Commercial Application in 1995
•First in the world (to the best of our knowledge)
Many similar products now on the market
Improved understanding
Not all answers are good – That’s Good!
Confidence in design
Our work is accessible to non-modellers
New answers
Metrics change
•Journey Time can now be supplemented with Journey Time Reliability
•Predictions of environmental impacts– all improved
•Effect of incidents / roadworks
New answers
The world is changing
•Managed highways
•Selective vehicle priority
•Driver education
•Ageing Population
Challenges
DATA, DATA, DATA
•Difficult to capture individual behaviour
•Difficult = Expensive!
SPEED
•Richer data
•Multiple runs
Challenges
Combining traffic microsimulation with other driver choices. For example:
•When to travel?
•How to travel (e.g. should I cycle or drive)?
•Where to travel?