Where you do your thinking
Right, this blog is supposed to be primarily about writing, not about my love of fast cars.
One of the reasons I really like driving is because I can think while I drive. That is to say, I like to drive and think alone; having another person in the car with me puts me under pressure to be interesting, and thus it's a little distracting.
You take the part of the brain that handles awareness and hands and feet, and leave it to do the actual driving on autopilot while the rest of the brain, metaphorically, takes a break and does the serious business of churning through ideas. It's not so hard when you've been driving for a while.
I've thought of some of my best scenes while on the road. I put on some music and drift, and work through whatever story is occupying my time. At some point I should really get a smartphone with a voice recorder so I can keep track of ideas, but that would probably require a car that wasn't made when I was still in school.
Yes, my Toyota is that old.
Everyone has a place where they do their writing. I do mine on my netbook, wherever I happen to be - and as long as I can listen to music, I can write anywhere and around anyone. But I do my thinking in my car.