The "car way" of telling how far the relationship is:

-- Trying to impress the woman: unlocks and opens the door, waits for her to get inside, closes her door behind her

-- Dating: the guy unlocks her door and then goes around to his side to get in.

-- Engaged: The man opens his door leans over and unlocks her door and opens it.

-- Married: The man gets in to the driver's seat unlocks the doors and says "Aren't you getting in?"