User:Jiangalang/Parking guidance and information

A parking guidance and information (PGI) system provides drivers with real-time information about parking space availability in specified locations. PGI systems aim to manage the available parking spaces in highly populated urban areas efficiently. Studies have shown that PGI systems can influence drivers’ choice of parking lot and reduce the time spent looking for a parking space, especially when many parking lots are near or at full capacity. PGI systems can be very general and only show the number of spots available in an entire parking lot. They can also be extremely specific and show how many spots are available in each aisle of a floor of a parking lot. The overall effect of PGI systems is a reduction in congestion and air pollution, which will result in the enhancement of urban areas.

History
The first known PGI system was installed in Aachen, Germany in the early 1970s. These earlier systems utilized very simple space counters and limited function signs to show parking availability. It was introduced to British in the late of 1970s and was later widely deployed in Japan and other European countries such as France. By the year 2000, PGI systems had become regularly used in over 75 locations. The technology is currently being implemented all over large cities in China due to the overabundance of vehicles in urban areas.

Implementation
A simple PGI system requires monitoring equipment placed at the entrances and exits of a parking lot in order to track the overall flow in and out of the lot. Different types of monitoring equipment can be used to track the flow, such as inductive loops, microwave radar, and infrared. The monitoring equipment will transmit data back to a central location for it to be processed and interpreted. This data can be transmitted through radio, microwave and infrared communications, leased line, Integrated Services Digital Network, Public Switched Telephone Network, fibre optic connection, and cellular telephones services. Variable message signs at sensible locations will display the relative information received, allowing for drivers to make a decision. A more advanced method of monitoring the availability of parking spaces would be to have a sensor installed into every parking space in a parking lot and have an LED indicator. The LED indicator would be separated from the sensor and would be placed along the aisle so that drivers could see if there was a free space from a distance.

Impact
By directing drivers to parking lots where there is parking availability, PGI systems will reduce the amount of time wasted searching for parking spaces and queuing at parking lot entrances. The search for parking spaces may be responsible for as much as 30% of the traffic on main urban roads. Time spent searching for a parking place can often reach up to 40% of the total travel time. The reduction of time wasted searching for parking spaces will decrease frustrations held by drivers who cannot find a parking spot. Congestion on traffic networks near the parking lots will be mildly relieved and allow for better traffic flow.

The use of PGI systems impact a wide variety of people, as listed below:

•   For drivers, parking spaces can be located and selected according to their needs, saving fuel and cutting operating costs, in addition to wasting less time. •   For traffic flows, delays caused by the inefficient search for parking spaces are reduced, while increasing the road capacity of the region through reducing queues that form while someone waits for a parking place to become free. •   For transport authorities, this system distributes demand efficiently, in addition to making it easier to control these operations with better data monitoring, simplifying the process of taking decisions and implementing plans. •   For transport operators, an increase in passengers carried is expected, due to either the expansion of Park and Ride trips, or through modal transfer encouraged through the implementation of more stringent parking control policies and the supply of related information. •   For parking managers, this system is beneficial because it helps parking lots reach the desired occupancy levels. •   For the environment, air pollution levels will likely drop, while enhancing a more appropriate use of urban areas.

The benefits from a PGI system will be greatest when the demand for off-street parking and supply are approximately equal. When there is an excess demand for off-street spaces, PGI is expected to have fairly little impact on problems caused. Signs would just continuously show the word ‘FULL’. On the other hand, if demand is sufficiently less than supply and spaces are easy to find, the system provides little benefit and might not be entirely necessary.