1. presented to Model Task Force Model Advancement Committee presented by Thomas Rossi Krishnan Viswanathan Cambridge Systematics Inc. Date November 24, 2008 Activity Based Models Review

2. 1 Presentation Overview Study Background and Objectives Models Studied Study Findings Discussion

3. 2 Study Background and Objectives Examine existing activity based models to determine model features, application procedures, and requirements Determine planning analysis needs for which travel models are used Summarize the ability of activity based models to provide accurate information for planning analysis needs

4. 3 Models Studied Urban Models San Francisco County, CA (2001) New York, NY (2002) Columbus, OH (2005) Sacramento, CA (2007) Lake Tahoe, NV/CA (2007) Atlanta, GA Portland, OR Denver, CO San Francisco Urban Area (MTC), CA

5. 4 Models Studied (Cont’d) Statewide Models Ohio Model (2007) Oregon Model Research Models FAMOS (University of South Florida) CEMDAP (University of Texas) TASHA (University of Toronto)

6. 5 Models Studied (Cont’d) SFCTA New YorkColumbusSacramento Lake TahoeAtlantaPortlandDenver San Francisco (MTC)OhioOregon Year Completed2001200220052007 2008 (est.) 2008 (est.) 2009 (est.) 20072008 (est.) Base Year20001996200020052000 20052000 Forecast Year202020302035203020352030, 2050 Survey Data Year199019981999200020011994199720002003No Survey Number of Households in Survey 1,30011,0005,6003,9001,2208,1006,0004,90015,000 No Survey Zones (approximate)1,700 (750 in SF) 3,6001,8001,5002892,000 2,8001,4545,3003,000 Area Size (square meters) 50 (SF only) 150 (est.) 4,0005015007,000 Base Year Population750,000 (SF only) 1,500,0002,000,00063,4484,700,0001,600,0006,783,760

7. 6 Study Findings Model Structure All models estimated from household activity/travel survey Same type of survey used for four-step model development Individuals in region’s population are simulated Activity patterns Locations and times of activities Modes used to travel between activity locations

8. 7 Study Findings Model Structure (Cont’d) Model structure Generate daily activity patterns Location, time and mode made at two levels : Tour and Trip Five to eight activity purposes Work, school, shop, meal, social/recreation, and personal business Some models consider household interactions Implications for time of day and mode choice Is it cost effective to include this to gain accuracy? The “jury is still out.”

9. 8 Study Findings Model Components Population Synthesizer Long Term Choice Models Auto ownership Usual workplace location Daily Activity Pattern Models Tour Level Models (primary activity) Destination choice Mode choice Time of day choice

10. 9 Study Findings Model Components (Cont’d) Trip Level Models (intermediate stops) Destination choice Mode choice Time of day choice Trip Assignment Highway Transit

11. 10 Study Findings Model Development Process Model development between 1.5 to 8 years (typically 2-3 years) Model development costs – typically $600,000-$800,000 Consultants nearly always used for model development Most models used local household activity survey data along with other sources such as transit on-board, external or visitor surveys Lake Tahoe model was transferred from Columbus

12. 11 Study Findings Model Execution Standard transportation modeling software such as CUBE/Voyager, TransCAD used along with custom programs in C++, Java, or Python Run times range from 10 hours to 2 days Distributed computing preferable to reduce runtime Models need around 7 to 10 GB of storage per run Most models run only in-house

13. 12 Study Findings Policy Planning Analysis Activity Based Models benefit the following types of analysis Congestion Management Systems Toll Feasibility Studies High-Occupancy Vehicle (HOV) Lane Studies New Starts/Small Starts Analyses Hurricane Evacuation Modeling Support Air Quality Conformity Determinations Integrated Land Use Model Incorporate Ability to Test Impact of Gasoline Prices Freight Studies Growth Management/Concurrency Applications

14. 13 Study Findings Data Needs No special data needs required to develop activity based models beyond what is used for four-step models Existing household travel surveys can be used to develop data for activity based models Other data sources such as transit on-board surveys, external and visitor surveys are also helpful for activity based models Census data sources such as PUMS useful for population synthesis ACS disclosure rules can be problematic

15. 14 Conclusions Models use similar approaches Main differences related to explicit modeling of household interactions Members of population simulated individually Their activities, locations, times, and mode choices Standard modeling software used along with custom programs Typically 2-3 years, $600,000-$800,000 to develop models Run times typically 0.5 to 2 days

16. 15 Discussion