I just returned from a trip to California. Southern California, in particular, is big on cars. Because of this, tools to solve car problems are often tested there.

One problem that we've all experienced is going into a parking garage and trying to find a parking spot.

If the garage is busy, it's often difficult to see where the open spots are, so one ends up driving up and down the aisles searching.

Well, I was going to have lunch with some friends at the Century City Shopping Center, and when I drove into the parking garage, I noticed two things:

First, a funny display that I didn't understand that had a series of colors -- orange, blue and red, if I recall correctly -- and next to each color was a digital display that included a number.

Second, as I entered the parking area, I noticed that above each parking spot, there was either a red or green light. Pretty quickly, I figured out that if the light was red there was a car in the spot, and if the light was green, the spot was available.

The beauty of this was that I could easily scan the parking garage and see where there were open spaces -- as indicated by the green lights.

I've been wanting this for years!

Once in my parking spot, I examined the devices to see how this was accomplished and figured it out. It's really pretty simple.

Above what would be the center of the parking spot (and presumably the roof of the car) is a device that most likely contains a proximity detector. Near the entrance to the parking space is a device that has some green and red LEDs.

When the proximity detector determines that there's something much higher than the garage floor, it sends a signal to the LEDs to indicate red (full), but when the proximity detector sees nothing higher than the garage floor, indicate green (empty).

It then hit me what the color display at the garage entrance was trying to tell me.

Each color-- orange, blue and red -- indicates a section of the garage. Sometimes they're levels, sometimes they are just different areas of the same level. In any event, the number associated with each color indicates the number of open (green) parking spaces.

So, along with each proximity detector turning on red or green LEDs, some central device keeps track of how many parking spaces are available in each section.

None of this is system is particularly difficult to implement, and now that it's working in at least one parking garage, I hope and expect to see it in more locations.

Mark Mathias is a Westport resident and has worked in information technology for more than 30 years. His "Living With Technology" appears every other Friday. He can be contacted at: livingwithtechnology@mathias.org