Katie Couric's Notebook: Green Lights

Cities across the country are making the switch to traffic lights that are always green.

OK, they still turn yellow and red, but they use environmentally friendly L-E-D bulbs that last longer and suck up 90 percent less electricity than incandescent ones. That's not only good for the environment, but for financially strapped communities which can save plenty of green.

But now that winter's here, there's a big yellow caution sign. L-E-D bulbs don't produce heat the way the old ones did. So, snow and ice can build up on lights during a storm instead of melting. That's already caused a lot of accidents and at least one death as drivers go through red lights because they simply can't see them.

Several states are trying fixes including weather shields. So far, heating elements have worked best, but they use even more energy than the old bulbs ... which would have plenty of people ... seeing red.

That's a page from my notebook.

I'm Katie Couric, CBS News.