Dogs couldn't be good drivers even if they tried. What I mean by that is they don't have the hands for it. A dog could be smart as a human, but without any hands to grip the wheel, it's not going to go down well. The dog could use its mouth, but then how are they going to see? When you think of it that way, you start to realize that maybe cars weren't built for dogs to drive.
For as much as people love their dogs, you never see a dog wearing a seat belt. Imagine if you crashed with a dog in the car. We freak out when our kids don't wear seatbelts, but not our dogs. Would you ever risk having your kid in the car without a seatbelt? The answer is probably no (unless you hate your kid).