Even if it was trained to drive like a human, it'd be better in many ways: It never gets drunk, doesn't get tired, doesn't get distracted, can drive old people (or anyone) around who shouldn't be driving anymore, etc.
I couldn't find the article, but i remember a project learning from remote control plane pilots. People mess up all the time. It's not even drunk or tired, there's just errors every so often, it's almost statistical. The little errors people make wash out as noise.
That's the first Terminator. Terminator 2 would be:
It would never leave him, and it would never hurt him, never shout at him, or get drunk and hit him, or say it was too busy to spend time with him. It would always be there. And it would die, to protect him.