SPATIAL AGGREGATION OF DISAGGREGATE CHOICE MODELS: AREAWIDE URBAN TRAVEL DEMAND SKETCH-PLANNING MODEL

This paper describes an aggregate urban travel demand model designed for areawide transportation policy evaluation with limited preparation of input data and fast response times. It does not include supply models but it can be used by itself for travel demand predictions with exogenously specified transportation level-of-service changes or it can be incorporated in the framework of the TRANS model. The methodology is generally applicable to urban transportation sketch-planning situations in which large geographic units are used. Aggregation is performed over spatial travel alternatives and spatially distributed individuals to produce required aggregate travel demand forecasts. An efficient solution method for spatial aggregation was developed that employs mathematical functions, expressed in terms of coordinates in the urban space, to describe the spatial choice process and to represent the geographic distribution of behavioral units, spatial alternatives, level-of-service characteristics, and locational attributes. This allows the spatial aggregation problem to be solved efficiently, by integrating the travel demand models over the urbanized area. Monte Carlo simulation techniques are employed and the procedure entails (a) generation of a sample of representative households distributed over the urban area using available census data, (b) generation of a sample of destinations for each trip purpose for each household, (c) computation of travel demand forecasts for each household based on the sampled destinations using a system of disaggregate travel demand models, and (d) accumulation and expansion of disaggregate predictions to produce aggregate forecasts. /Authors/

Media Info

  • Media Type: Print
  • Features: Figures; References;
  • Pagination: pp 93-99
  • Monograph Title: Transportation forecasting and travel behavior
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00195997
  • Record Type: Publication
  • Files: TRIS, TRB
  • Created Date: Sep 15 1981 12:00AM