Hey, Wendy:

Any chance you could drive your car up on stage and let Bily Bob sing with the windows rolled down? It's much easier than having a shower on stage. Or a Men's Room. Those are the other places where shy folks burst into song. It's all about a contained space, I think.

I've written a majority of my songs over the years, while driving.
It just seems to be a fertile environment for creation (I'm talking front seat creation, here.) Over the years, I've had a habit of just singing a line that comes out of nowhere. Most of the time, I'd look like an idiot, if somebody heard me. Which is why I sing with the windows rolled up. But once in awhile, a line comes out that really interests me, and it evolves into a song.

Some first lines, out of nowhere that became songs:

"Put another bowl on the floor, Mildred, I think Rosco's got a friend"

"Old Dog Trey, he's out on the backporch sleeping"

"It was a nice night, at least I thought it was nice"

"ooh-wee, wouldn't you liked to've been there? Wouldn't you liked to've been there in the morning?" (This one never became a song, and I still don't know why I would've liked to have been there in the morning.

There are many others... not all of which came while driving. But, even those that initially came out of some other situation (dreams, as often as not) became songs as I kept singing the lines that I had, while driving.

The disadvantage of writing songs while you're driving is that it's dangerous to actually "write" them. My attitude on that is that if I can't remember the melody the next day it is by definition, not memorable. And who wants a melody that isn't memorable, anyway?
Besides, I can't write music, so I couldn't "write" a song if I was sitting in a Barcalounge wearing a velvet smoking jacket with leather elbow pads.

Jerry