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Report
Activity Based Modeling: A Brief
Introduction
Florida Model Task Force
Meeting
November 29, 2007
Mike Neidhart, PhD, AICP
Volusia County MPO
MTF – 2 Track Focus

MTF work can be divided into 2 frames of
thought (or tracks/focus)
–
–
Research based on how we can incrementally
improve our existing model framework
Research model frameworks/philosophies that
are 5-10 years into the future such as
incorporation of meso and/or micro models,
Activity Based models, etc.
• This presentation will be on Activity Based
Models
AMB Background


Activity Based Models (ABM) predict travel
behavior as a derivative of activities (i.e.,
derived demand)
Travel decisions are part of a broader
process based on modeling the demand for
activities rather than merely modeling trips
AMB Background Continued

ABM belongs to the 3rd generation of travel
demand models
–
–
–

Trip based 4-step models
Disaggregate trip based models
Activity based models
In ABM the basic unit of analysis is the
activities of individuals/households
AMB Background Continued

ABM are based on the theories of
Hägerstrand (1970) and Chapin (1974)
–
–

Hägerstrand focused on personal and social
constraints
Chapin focused on opportunities and choices
Theory is that activity demand is motivated
by basic human desires for: survival, ego
gratification, and social encounters
Activity Demand


Unfortunately, it is difficult to model activity
demand
However, research indicates that household
membership moderates activity demand
such that:
–
–
–
Households influence activity decisions
Effects differ by household type, size,
membership relationship, age, and gender
Children impose significant demands and
constraints on others in the household
ABM Approach (slide content: E. Zwerts)




Travel demand is derived from activities that
individuals need/wish to perform
Sequence/patterns of behavior, not individual
trips, are the unit of analysis
Household and other social structures
influence travel and activity behavior
Spatial, temporal, transportation, and
interpersonal interdependencies constrain
activity/travel behavior
ABM Approach (slide content: E. Zwerts)


Activity based approaches reflect the
scheduling of activities in time and space
Activity based approaches aim at predicting
which activities are conducted where, when,
for how long, with whom, by mode, and
ideally also the implied route decision
ABM Paradigms (slide content: G. Jovicic)

ABM rely on the following 5 paradigms:
–
–
–
–
–
Travel is a derived demand from activity
participation
Focus is on the sequence of activities/events
Activities are both planned within the context of
the household
Activities are spread over a 24-hour period in a
continuous manner rather than using “peak” and
“off-peak” periods
Travel choices are limited in time, space, and by
personal constraints
Hypothetical Travel Day
Graphic by Goran Jovicic
How To Model Trips (slide content: G. Jovicic)



Trip-based model would model all 7 trips
independent of the other trips
Tour-based model would model Tour 1 and
Tour 2 independent of each other, while the
Work Tour would be modeled as two
independent trips
ABM would model the 4 activities and
associated trips (work, meeting, shopping,
and movie) as part of the same decision
process
Criticism of Trip Based Models


Poor forecasting accuracy of trip based
models most likely due to the model’s
theoretical mis-specification
Trip based 4-step and disaggregate models
have a fundamental error – they analyze
each trip independently of other trips made
by the individual
–
Trip based models fail to recognize the linkages
among trips, between trips, and the activity
participation by the individual
Advantages of ABM

Theoretically based on human behavior
–



Better understanding and prediction of traveler
behavior
Based on decision-making choices present in
the “real-world”
Use of disaggregate data
Inclusion of time-of-day travel choices
References




Jovicic, G.: Activity Based Travel Demand Modelling: A
Literature Study. Danmarks TransportForskning
Publishing, Note 8, 2001.
Bowman, J. L. & Ben-Akiva, M.: Activity Based Travel
Forecasting. tutorial on activity based travel forecasting
taught at conference of same name in New Orleans,
Louisiana, June 2, 1996.
Shiftan, Y.; Ben-Akiva, M.; Proussaloglou, K.; deJong, G.;
Popuri, Y.; Kasturirangan, K. & Bekhor, S.: Activity Based
Modeling as a Tool for Better Understanding Travel
Behaviour. Paper presented at the 10th International
Conference on Travel Behaviour Research, Lucerne,
August 2003.
Zwerts, E. (in cooperation with E. Moons & D. Janssens):
Activity-Based Modelling: An Overview. PowerPoint
presentation, Limburgs Universitair Centrum, Universitaire
Campus, gebouw D, 3590 Diepenbeek, Belgium.

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