If you have driven in a German city of any size looking for a parking spot, you might have noticed signs like the one pictured here. The signs not only give directions to nearby parking garages, but also tell you how many places are available at each garage. The idea is to help save time, gas, traffic congestion and pollution by leading drivers directly to a garage with empty parking spaces.
Signs like these are possible because all the parking garages uses a similar system to control entry and exit from the garage. The driver pulls a ticket from an automat, thus initiating the lifting of the gate allowing the driver to enter the garage and then lowers the gate At the same time the automat is able to reduce the number of available parking spaces and transmit that to a computer to update the signs all over town. On returning to the garage to pick-up your car, the ticket is paid by inserting the ticket in an automat typically near the garage entrance. The automat figures the cost and displays it to the driver. Once the driver has paid, the automat marks the ticket as paid and returns the ticket to the driver. The driver then has about 15 minutes to find his/her car and leave the garage. At the garage exit, the ticket is inserted into a third automat. This automat lifts the gate allowing the driver to exit, increases the number of available parking spots, transmitting the change to a computer to update the signs and lowers the gate after the car has exited.
A new parking garage has opened in Koblenz that takes this idea to a new level. At the end of each row, there are two signs. One tell the number of parking spaces available in the row. The second tell the number of avail parking spaces if you continue further in the garage. Now in a nearly full parking garage, this is a pretty neat thing. No more driving down row after row looking for one of the last open spaces, hoping that someone else does find them first. But how is this done? I mean there are no gates on the individual parking spaces.
Well no, but there are sensors over each parking space. Here you can see that the sensor glowing red has detected our car in the parking space it monitors. Meanwhile, the sensor over the empty parking space next to us glows green.
