Methodology to Match Distributions of Both Household and Person Attributes in Generation of Synthetic Populations

The advent of microsimulation approaches in travel demand modeling, wherein activity-travel patterns of individual travelers are simulated in time and space, has motivated the development of synthetic population generators. These generators typically use census-based marginal distributions on household attributes to generate joint distributions on variables of interest using standard iterative proportional fitting (IPF) procedures. Households are then randomly drawn from an available sample in accordance with the joint distribution such that household-level attributes are matched perfectly. However, these traditional procedures do not control for person-level attributes and joint distributions of personal characteristics. In this paper, a heuristic approach, called the Iterative Proportional Updating (IPU) algorithm, is presented to generate synthetic populations whereby both household-level and person-level characteristics of interest can be matched in a computationally efficient manner. The algorithm involves iteratively adjusting and reallocating weights among households of a certain type (cell in the joint distribution) until both household and person-level attributes are matched. The algorithm is illustrated with a small example, and then demonstrated in the context of a real-world application using small geographies (blockgroups) in the Maricopa County of Arizona in the United States. The algorithm is found to perform very well, both from the standpoint of matching household and person-level distributions and computation time. It appears that the proposed algorithm holds promise to serve as a practical population synthesis procedure in the context of activity-based microsimulation modeling.

Language

  • English

Media Info

  • Media Type: DVD
  • Features: Figures; References; Tables;
  • Pagination: 24p
  • Monograph Title: TRB 88th Annual Meeting Compendium of Papers DVD

Subject/Index Terms

Filing Info

  • Accession Number: 01128672
  • Record Type: Publication
  • Report/Paper Numbers: 09-2096
  • Files: TRIS, TRB
  • Created Date: Jan 30 2009 6:26PM