The automobile represents the human personality running the regular grid pattern of its programming. A driver's license is the physical statistics of the person as well as their name.
The metaphor of a car leaving the garage is a baby leaving the womb. If you find yourself, in your dreams, in a garage with the door closed, it is the time just before a birthday, perhaps your own. The garage door opening is the birthday and the garage door fully opened is the time just after a birthday.
A parking lot is a prison yard.