TRB's second Strategic Highway Research Program (SHRP 2) Report S2-C46-RR-1: Activity-Based Travel Demand Models: A Primer explores ways to inform policymakers' decisions about developing and using activity-based travel demand models to better understand how people plan and schedule their daily travel. The document is composed of two parts. The first part provides an overview of activity-based model development and application. The second part discusses issues in linking activity-based models to dynamic network assignment models.