You guys don't understand. The car represents the girl's growing of age and being able to drive a vehicle, and the "vroom vroom" is a sign of her excitement to drive aka grow up. While the mother wants her to stay young and innocent, "get out me cah" is her wanting the daughter to remain a little girl instead of grow up aka drive. The girl's sigh at the end can be seen as her disappointment, and feels no longer the excitement of growing up aka driving.
NOOOOOOOOOO OMG
