The congestion tax system architecture consists of four principal components:
roadside equipment to collect passage information
pre-processors, to process the information from the control points and generate tax decisions
a business process platform, to book tax decisions, handle payments, reminders and reports
a web portal – with both a public website and an Intranet for the benefit of Customer Services and the National Tax Board.
Regarding road side equipment, the technical equipment at a control point is installed on three gantries above the carriageway and in a control cabinet at the side of the road. Columns are used instead of gantries at some control points. The first gantry is equipped with a ”Control Point” sign as well as a digital display indicating the tax charged at that particular time. Cameras installed on this gantry are used to photograph the rear number plates. The cameras used to photograph the front plates are mounted on the third gantry. Laser detectors and transceiver aerials for vehicle identification via the onboard unit are mounted on the middle gantry.