This project focused on studying Automated Carpool Detection Systems for High Occupancy Vehicle (HOV) Lane Monitoring. The final report provides a basis on which electronic / automated processes for monitoring HOV / Height Occupancy Toll (HOT) lanes can be developed. It outlines a number of viable concepts to be considered for development, demonstration, and/or field evaluation. The results were compiled through a comprehensive review of current practice and previous research, and consultation with members of the transportation industry including law enforcement, auto manufacturers and transportation planners. The study demonstrates the feasibility and potential benefits of automating the occupancy detection task, and highlights the social concerns and commercial issues that need to be addressed.