The Comprehensive Econometric Microsimulator for Daily Activity-Travel Patterns (CEMDAP) is a microsimulation implementation of an activity-travel modeling system. Given as input various land use, sociodemographic, activity system, and transportation level-of-service attributes, the system provides as output the complete daily activity-travel patterns for each individual in each household of a population. The underlying econometric modeling framework and the software development experience associated with CEMDAP are described. The steps involved in applying CEMDAP to predict activity-travel patterns and to perform policy analysis are also presented. Empirical results obtained from applying the software to the Dallas-Fort Worth area demonstrate that CEMDAP provides a means of analyzing policy impacts in ways that are generally infeasible with the conventional four-stage approach.