Hi Wackers,
Having panic while driving is very common. Many people experience this as either the driver or passenger, so know that you are not alone.
In our Resources, you will find great exercises to reduce panic such as these links.
http://www.ehow.com/video_4405003_breathing-exercises-panic-attacks.html
http://www.psybersquare.com/anxiety/panic_relax_I
Practice this along with other coping skills to reduce overall anxiety levels, and so that you can know these exercises very well and have them ready when and if you need them.;)
Keep posting with us!
S.C.