And the authorities have long exacted road tolls for the same reasons. It works much like a miniature version of the electronic turnstiles at mass-transit rail stations.
Motorists insert a cash card into the unit when they are on the road.
And as their cars pass overhead gantries set up along the strategic roads, the card-reader is activated by a microwave signal. There is a beep and the toll is deducted from the stored-value card. Errant drivers who don't keep their cards topped up or, worse, fail to install the gizmo, will be swiftly slapped with a salutary fine. Cameras mounted on the gantries record the vehicle's plate number. Computers match it against government records, and a traffic ticket is on its way to the registered owner in no time.