Methods and systems for selecting a target vehicle for occupancy detection utilizing vehicle identification information. The vehicle identification information (e.g., license plate information) can be obtained from a vehicle identification unit (e.g., ALPR) to identify a vehicle approaching a high occupancy measurement zone. The vehicle identification information from the vehicle identification unit can be transferred to a vehicle occupancy unit having a flash illuminator unit and an image-capturing unit. The flash illuminator unit and the image-capturing unit are not enabled if the vehicle's occupancy state has already been measured at a prior location based on the vehicle identification information. The vehicle occupancy detection unit and the vehicle identification unit work together in a coordinated fashion to reduce the number of times the flash illuminator unit needs to fire and extends the life of the illuminator unit, thus reducing the cost of maintenance.