I went from 5 degrees to 40 yesterday, so things are looking up. As the temperature improves, I shed the weight of winter: wool coat, boots, gloves. I even washed Michigan off my car so that the wheels and brakes can move without the scrape of ice globules.
As I said earlier, drive time is when I think about a story and look for ways to tell it better. Immersed in the typing-and-composing thing, I often lose the big picture: where is the story going, what are the characters learning that changes them, and how enjoyable the ride is for the reader. I've heard many authors talk about how hard it is to cut a story, to leave out bits that we like, but as I ride along, I analyze what can be left out, what isn't essential to the whole. I also look at the characters and imagine them talking, so when I return to the keyboard I can test whether I've made them sound like themselves and not like each other.
I believe that writing needs equal time at the keyboard and away from it, half in actual composition and half in (semi) objective analysis. It's only when we step away that we can see the larger view, and it's usually when I'm driving that I have the time to see both backward and forward in my story, to see if it creates a sensible picture.