If you have a dream where you are a driver it means that you are in control of your destiny. Your mind is reaffirming the hold that you have over yourself and your own ability to go out there and make sure that you accomplish what needs to be done and you get all of your goals out of the way.
If you have a dream in which you are in the driver seat of a car it means that you feel extremely confident about what you are doing and you feel like you have done a lot of work recently which has required you to make some pretty tough decisions. Luckily it is because of all of this hard work that you have been able to get past all of the tough work that you have been through up to this point. You have done a good job and you are the master, or at least you feel like you are, and that is what is most important.