How to be Productive While in the Car

I spend many hours every week in the car between commuting to work and driving places for my work.  I used to listen to the radio but as my life became busier and busier I wanted that time to be productive in some way to allow me to relax when I got home.  These are the four ways I try and use the time in my car and all of these ways use my smartphone.

1. Listen to podcasts
The first way I thought about being more productive was to make myself a better person by listening to self-help items on the radio.  I found that it was easier for me to find items that could educate me in a number of different areas.  To load the podcasts onto my smartphone I use iTunes along with SyncTunes (the free version).  I chose podcasts dealing with personal finance (Dave Ramsey and Money Girl), religion (Your Move), and psychology (The Savvy Physiologist).