Automated Enforcement of vehicle occupancy verification is a major challenge for efficient operations of High-Occupancy-Vehicle (HOV) or High-Occupancy-and-Toll (HOT) lanes.Several partially-and fully-automated techniques for determining the number of persons in a moving vehicle have undergone limited field testing.However,no automated solution has yet been developed for permanent field implementation, and no system has been proven to satisfy legal and institutional requirements.As a result, HOV/HOT facility operators have traditionally relied on field enforcement by police officers to manage occupancy violations.A breakthrough was made in 2013 in Chinese Taipei when a vehicle occupant detection system was deployed on an expressway and it has been continuously operated since then.The image-processing based occupant counting system was implemented along with wireless technologies to provide message sign warnings for drivers as well as violator information for police officers.This represents a pioneering first-in-the-world implementation of such systems.In this paper, we report the concept of operations and the system configuration of the deployed HOV monitoring system in Chinese Taipei.Some technical and institutional issues to be further investigated are also discussed.