Everyone is short on time and long commutes do not help with this! To fit in some strength training on the freeway, I have created a series of arm movements (one at a time, of course) that I can do while driving. These involve pulsing pushing arm circles etc. Just put on some music and experiment!
Use one arm at a time and work on it until you can't keep it in the air any longer - I try to do at least 5 minutes on each arm. Mix and match a varierty of movements that target different muscles. Just be sure the other hand is on the wheel at all times. Inspired by Tracy Anderson arm workout.