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This presentation by Stephen Cragg from SIAS Limited explores the complexities of modeling individual vehicle and driver behaviors. It covers methodological approaches, key achievements, and ongoing challenges in the field. Key influences on personal travel, including demographic factors and lifestyle choices, are examined. The discussion also highlights traffic and transport models, behavior models, and the importance of driver characteristics in decision-making. With the ever-changing landscape of transportation, the presentation emphasizes the need for richer data and effective predictions regarding journey time reliability and environmental impacts.
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Modelling individual vehicleand driver behaviours Stephen Cragg Associate – SIAS Limited
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 Traffic Models Traffic Models Transport Models Driver & Vehicle Behaviour
A model NOT in S-Paramics!
Behaviour model • Logic based If this situation occurs Then do this based 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? • 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 this situation occurs Then do this based 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 spread
Distribution modification • Not all distributions are normal • Apply a skew
Vehicle characteristics • Top speed • Physical rather than legal • Bounds of acceleration / braking • Dimensions • Length, width, height and mass
Overview • Methodological approach • Key achievements • Current and future challenges
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
Overview • Methodological approach • Key achievements • Current and future challenges
Challenges • DATA, DATA, DATA • Difficult to capture individual behaviour • Difficult = Expensive! • SPEED • Richer data • Multiple runs
Challenges • Language • Micro and Small are NOT synonyms • Education • Different mindset
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?