Satellite controlled congestion charging technology has become a serious competitor to gantry mounted electronic tolling systems, according to a study carried out in Hong Kong.
Mass production of in-car transponder systems is expected to drive down unit costs of satellite-run vehicle positioning systems. This is likely to make them as cheap as systems relying on the construction of large numbers of gantries.
Independent consultant Ian Catling carried out the study for the Hong Kong Department of Transportation.
He told a recent Intelligent Transport Society forum that the higher cost of VPS would be offset by the nominal infrastructure cost.
Satellite infrastructure costs would be further lowered by US President Clinton's decision to end selective availability of US satellite signals for civilian use. This means vehicle locations can be pinned to within 20m instead of 100m.
VPS systems can deduct charges from a pre-inserted smart card or transmit them to a central accounting system.