Parking Guidance and Information (PGI) systems use variable message signs (VMS) to provide drivers with information on the location and the availability of spaces in car parks. They have been in use since the 1970s, initially implemented in Aachen ( Germany ). Over subsequent years, their use has increased and it has been estimated that over 50 systems of this type are in operation worldwide.
Earlier systems involved limited function signs with very simple space counters and availability display units. However the technology used has evolved and nowadays electronic message signs are able to display a full range of messages and symbols.
A typical PGI system consists of m onitoring equipment to establish the flow into and out of the car park, a central computer to process the counts and control the dissemination of information to the public via VMS or other media such as radio or a web site. VMS displays should be located at suitable decision points on the network, so that a driver’s journey time to a vacant space is minimised.
The aim of PGI systems is to manage the available parking spaces in highly populated urban areas more efficiently. Studies have shown that PGI systems can influence drivers’ choice of car park and reduce the time spent looking for a parking space. This affects traffic flows and queueing outside the most popular car parks. The overall effect is a reduction in congestion and air pollution which will lead to enhancement of urban areas.