Disaggregate travel demand models for large metropolitan areas and their reliability over time

Statistical stability of the travel demand models over time is not conclusively reported in previous works which have demonstrated the significance of several factors in trip making such as income, household size, automobile ownership and population density. This study examines travel demand models over time using United States Nationwide Personal Transportation Survey (U.S. NPTS) datasets. The role of new variables such as life cycle stage and distance to public transportation are tested in the models.; The analyses show that a systematic relationship exists between the life cycle stage and the number of trips generated daily by a household; and between the distance of a household to public transportation facilities and the number of automobile and public transportation trips made by a household. The life cycle stage models show the highest travel activity in a household consisting of two adults and school-aged children. As expected public transportation model show a declining trend in public transportation trips as a household is located further away from the nearest public transportation facilities. The other socioeconomic models developed in this research are similar to previous findings in many aspects except household income and vehicles ownership.; All of the models developed are not stable over the three time periods tested.