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SimAGENT for SCAG Simulator of Activities, Greenhouse Emissions, Networks, and Travel. Introduction
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1. SCAG ACTIVITY-BASED TRAVEL DEMAND MODEL (SimAGENT) Kostas Goulias
University of California
Santa Barbara
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2. SimAGENT for SCAGSimulator of Activities, Greenhouse Emissions, Networks, and Travel Introduction & Definitions
Examples Policy Analysis Needs
Simagent Phase 1
Simagent Phase 2
Project Tasks and Management
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5. Conventional (zonal) Models (spatial structure representation) 5
6. Conventional (zonal) Models(travel behavior representation) 6
7. The 4-step Model 7
8. Improved 4-step 8
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11. A Person’s Daily Travel Pattern (conventional model) 11
12. A Person’s Daily Travel Pattern (activity based model) 12
13. Two Other Household Members Travel Pattern (activity based model) 13
14. All Household Members’ Travel Pattern (activity based model) 14
15. On the zonal system (activity based model) 15
16. Some Key Aspects of Activity Based Models Trips are linked for each person in a day
Timing and durations are included
Entire daily travel patterns are linked
Car use is associated to needs (take child to school, drive together to shop & dine and back )
Removing a trip or activity has a domino effect on everything else that is not “fixed” 16
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18. Examples of policy analysis needs 18
19. Congestion Pricing Toll strategies/pricing
Impose a toll and predict elasticity of demand (-0.1 to -0.4)
Conventional models
Predict shifts in departure & arrival time
Observed elasticity lower than predicted
Why?
Time offset (freeing capacity taken by others)
Value of time very different among segments
Entire activity-travel schedule modified by pricing
Activity-based models could address these issues
Predict who reacts to policy at the individual level
Predict activity scheduling and task allocation changes within households
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20. HOV/HOT Conventional models
HOV as a mode (time and cost)
Overestimate the number of users
The problem is lack of accounting for intra-household interactions and carpool formation
Activity-based models
Include hh-member interactions
Include a car assignment to person model/routine 20
21. Parking Conventional models
Parking duration not modeled
Parking lot = destination of trip
Summary demand by period of day
Activity based models
Explicit estimation of parking duration
Operate at fine temporal resolutions
Can keep track of cars in households 21
22. Transit fare Conventional models
Zone to zone base fares
Examine changes in ridership and correlate with fare changes
Activity based models
Transit paths can be developed
The impact of waiting times and costs examined in terms of overall change in scheduling
Too much work? Should we calibrate this to potential for change?
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23. Shorter days and weeks Conventional models
Not sensitive to work duration
Impose change in trip generation and see what happens
Activity-based models
Activities, travel, and duration of activities are tied together
Changes in work duration and days of the week are explicitly modeled (increases in after work periods, available extra day to do other things and so forth) 23
24. Demographic shifts Conventional models
Very few segments
Operate at OD level
Activity based models
Operate at the individual and household levels
Include full-time vs. part time workers
Include children by age groups
Include many additional segmentations because of synthetic population generation
Key to this region ethnicity! 24
25. Car ownership and type Conventional models
Absent
Number of cars per household
Activity-based models
Explicit car ownership and assignment to persons
Type can be incorporated (including fuel type) 25
26. Emissions inventory Conventional models
Vehicle activity is handled by post-processing
Does not account for within household vehicle assignment and does not produce a vehicle trace -> loss of vehicle use profiles
Activity-based models
Details about who uses each vehicle and when/where
Some produce traces of vehicles during the day
New generation emissions models may be more compatible (?!) with this approach
Some explore dynamic traffic assignment but not final word yet! 26
27. Land use & development Conventional models
Build scenarios and data fed into 4-step
Zone to zone travel time and costs (accessibility indicators) used in land use
Can be done in an feedback fashion for lagged time
Activity based models
Offer opportunity for true integration
Land use driven by location desires (and developer desires)
Travel models use more detailed land use data
We hope for parcel detail but many issues are not solved yet
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29. SimAGENT Vision Comply with the California Transportation Commission (CTC) 2008 guidelines for RTPs
Create an activity-based model that can address wide range of policies, including:
Economic analysis: location-based welfare, wages, and exports
Equity analysis: change in welfare by household income class
Evaluate the energy use and GHGs produced by households and workers in building space
Comprehensively evaluate economic development impacts
Evaluate time-of-day roadway tolls 29
30. Phase 1: Adapt CEMDAP-DFW to SCAG SimAGENT 30
31. Phase 1: Adapt CEMDAP-DFW to SCAG SimAGENT 31
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33. Phase 1 Comparison of Model Scale SCAG 2003 Validated Model
4192 zones (4,109 internal + 40 cordon, 12 airport, 31 port)
Used also for air quality and GHG (CO2) emission estimation with EMFAC
Highway network includes freeway system (mixed-flow lane, auxiliary lane, HOV lane, toll lane, truck lane, etc.), arterials, major collectors, and some minor collectors
AM peak period (6:00 AM to 9:00 AM)
PM peak period (3:00 PM to 7:00 PM)
Mid day period (9:00 AM to 3:00 PM)
Night period (7:00 PM to 6:00 AM)
No Dynamic Traffic Assignment
Traditional feed forward land use and assignment Dallas – Fort Worth CEMDAP Study
4,874 Zones (4,813 Internal + 61 External), 18,566 network nodes
22,185 roadway links (26,799 lane miles) + 9,600 zone connector links
63 HOV links (37 lane miles)
Highway network used with CEMDAP includes freeways, HOV lanes, major arterials, minor arterials, collectors, ramps, frontages, etc.
Morning off peak (3:00 AM to 6:29 AM)
AM peak (6:30 AM to 8:59 AM)
Mid day off peak (9:00 AM to 3:59 PM)
PM peak (4:00 PM to 6:29 PM)
Evening off peak (6:30 PM to 2:59 AM)
Also tested Dynamic Traffic Assignment
Includes key aspects of the integrated model 33
34. PHASE 2: Development of Advanced Version of SimAGENT (2011) Increase spatial detail
Accessibility reflected in major interactions
Expected to have:
Sensitivity to an expanded repertoire of policies
Integrated land use influences on travel behavior
Enhanced feedback among model components
Enhanced reflection of behavioral interactions
Integrated interfaces with land use, traffic assignment, and EMFAC and/or MOVES 34
38. PROJECT TASKS AND MANAGEMENT 38
39. Project Tasks 39
40. Tasks-Schedule-Budget 40
41. Project Deliverables 41
42. Project Deliverables 42
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