Last night after work, I had to go to a meeting over 1 1/2 hours away. I knew I wouldn't be getting home until after 11 p.m. and not have time to exercise so I decided to walk in my car. Let me tell you that moved muscles in my legs I didn't know existed. I just set my cruise control and took off. The first time I did 5 minutes on the drive there. On the way home I broke it up to a 10 minute session and then a 15 minute session. It was kind of hard to try and set my foot down like you normally would when walking and I guess that's why it worked some other muscles.
Although I know it's not something I could do on a regular basis but since I have a 30 minute drive to work and then a 30 minute drive home it may be something to do when I find I don't have the time to get in some exercise for the day.