Had a heavy frost this morning, warmed up the car, defrosted the windows, all was well. Took off down the street, noticed that my headlights were almost non-existant in the dark. Flipped them on/off/on again. Could tell lights were on but not bright. Stopped and looked. The glass covers of the headlights were frosted nicely. Never had a car with these types of headlights before. I guess it needs to have the lights on to defrost them properly since they were fairly easy to wipe off with my hand when I stopped to check them. Made mental note to remember to turn on the headlights when warming up the car in frost.