I decided to google this, since I am on Duragesic, and drive all the time. I do not feel impared in the least, and figured there must have been some studies on this subject, and in fact here is a link, proving that people who have been on Duragesic for a long time, suffer no motor skill issues. I would think these studies would hold up in a court of law.

http://opioids.com/fentanyl/ability.html