Validation and Assessment of Activity-Based Travel Demand Modeling Systems

The past decade has seen the rapid development of activity- and tour-based travel demand modeling systems. Several metropolitan planning organizations (MPOs) in the United States and metro areas in Europe have implemented such systems to take advantage of the derived nature of travel demand and interdependencies among trips. Despite the appeal of these models, their widespread implementation appears to be hindered by the absence of a detailed validation and assessment of this new wave of model systems. Many MPOs will not adopt such models until they are tested. These sentiments were expressed 10 years ago in New Orleans at the Travel Model Improvement Program (TMIP) Conference on Activity-Based Travel Modeling and more recently in e-mail forums such as the TMIP Listserv. This conference in Austin brings model developers and MPO staff together to discuss validating and assessing activity-based models.