Couldn't We Use Technology to Save Energy

There was a commentary in the San Francisco Chronicle by Jon Carroll. In it, he asks why so many of the big city buildings in San Francisco leave their lights on all night. I was asking myself the same thing a few days ago when my dog woke me up at three in the morning needing to go outside. I was looking at all the buildings that had their lights on. Could that be a hospital? One building caught my eye that had the lights on every floor lit up. Then I looked around the rest of the city and there were lots of buildings with the lights on. I started to wonder what the cost would be for installing motion sensors that would turn the lights off if no one was moving around. I found an article in the New York times, The Cost of Saving Energy, that says it would take an apartment building only 2 years to recoup the cost of installing motion sensors in hallways and stairways that turn the lights down to 50% when there's no one around.

So the question really is not "Why are we leaving the lights on?" Instead the question should be, "Why isn't there a system to turn the lights off?"

I looked up at the sky for the constellations. There's only a few that are viewable because there are so many lights on in the city. Could it be possible that twenty years from now, we'll be so consious about saving energy that we could see more stars in the sky at night?