peter doocy in the cold in evanston, illinois. what's the problem with these new l.e.d. intersection in a blizzard. you look up to see if your signal will be green, yellow or red. and it's white. thousands of intersections across america are installing energy efficient light emitting diode traffic signals because they use 90% less energy. they save towns so much money that one suburb, their energy bills stopped at that one intersection from $63 a month to less than $10. they don't get very hot and if they get snow on them in a storm, it's there, it's not going to melt off. we know this has wreaked havoc on commuters and drivers. it has caused accidents and at least one fatality. trace: what does the city do to keep these lights clear? >> some cities are look at heating elements which is a device that gets attached to the light and if there is snow on it it melts it off. but that adds 50% to the energy bill. when you factor in the cost of the hardware. in evanston they have had a few problems with traffic lights being covered by the snow. even though the lights are high-t

let's get to evanston where peter doocy has been ensuring -- enduring cold and ice in the last couple of days. >> just a little. the light emitting diodes sound like a treatment come true to cities and towns looking to save money in the long term because they use 90 percent less energy in the incan decemberent bulbs which savings energy and the state of wisconsin recently switched about 90 percent of the traffic signal that is they control over to led, a savings of $750,000 a year for them. say what you will about the old fashioned incandescent traffic signals but they got hot, hot enough to melt snow. these new led light, they just don't get hot because they don't use a lot of energy, and when it snows on them, it doesn't melt, which is a nightmare for drivers. you can't tell what the signal is. and in blizzards, several times accidents have been caused, including at least one fatality, because drivers get to an intersection looking for red, yellow or green and they see white and don't know what to do. >> so what are the cities doing about t. then, the ones who already have the light