Highway usage is monitored, managed, and analyzed through a series of antennas, sensors, cameras, and computers networking in realtime. If the antenna detects a transponder, it tracks the vehicle for a short distance in case the vehicle changes lanes as it passes beneath the gantry. If the antenna doesn't detect a transponder, it instructs a digital camera on a second gantry to photograph the vehicle's rear license plate. Data, in the form of transaction reports and digitized images, is then relayed to an administrative center for billing. Regular commuters can choose to establish a prepaid credit account based on estimated monthly usage, arrange for direct debit from their bank account, or receive a monthly invoice.
Occasional users receive an invoice, which includes a small video billing surcharge.
Each tolling point or station contains up to six different types of equipment that must interact with each other in microseconds. In the event of a network interruption, the QNX system contains a hard disk that spools data. The two processors match entry and exit data with vehicle information. They also read license plates using technology originally developed to guide missiles in Desert Storm. All information is then transmitted to a revenue management system, which generates invoices.