The car would still use its sensors as Judgement. Reason I even posted this is I auto park my car into my two car garage all the time. For some reason, no matter how much I pull to the far right, my car keeps wanting to dominate the garage..lol
I was going to keep my response to 1 sentence, but that turned into a huge response, sorry in advance.
Unless I'm misunderstanding you, you're WAY underestimating the problem.
The sensors can do well to help you avoid hitting a parked car, because they rely on the reflections from the radar/sonar. But if you park at an angle, and have the car drive forward, what you're asking for is for the camera (not sensors) to help you decide where to do. That's a MUCH harder problem.
From a human perspective, you see a garage, you know it's a garage. From a machine learning perspective, you see one garage, then you see another garage, how can you tell that the 2nd one is a garage? What if one is open and the other is closed, you need to teach the machine to be able to recognize a garage door.
Then if you have a two car garage, and you make it learn to go into the left stall, for example, the computer needs to be able to learn what a left stall is. The computer needs to be able to say with a reasonable amount of certainty "yes, that's a garage" if it's light outside, dark outside, raining, etc.
Think of it like this - having the car use sonars to tell the car the distance from an object is a 1-dimensional problem. You have distance from your bumper (16 distances, but still 1-dimensional). Having the camera help guide you, means the camera needs to know what to look for. With a human in the loop (or a human training the system), the human can say "align yourself to the left garage post in Person A's house, the right garage post in Person's B house, the pink dresser in Person C's house, etc.", but what you're asking for is for the system to do this automatically. You're taking a simple 1-dimensional (drive back and forward and not hit anything), into a multi-dimensional problem (drive back and forward, and orient yourself using things you see in MY house. But when you're at someone elses house, and I hit learn, I need you to learn to use their light post as a way of orienting your direction of travel).