There are many Somali immigrants in Minneapolis. The bank near where I work has quite a number of Somali employees, who are primarily Muslim. This car, I believe, belongs to one of these employees, since it is parked in the lot all day including before the bank is open.
I couldn't help wondering when I saw this why it was okay for an (I assume) observant Muslim to put the name of god in such a crass location as a license plate, but it is not okay for children in a class with a non-Muslim teacher to name a teddy bear after Muhammed.
Although I supposed it's possible that there might be disagreement in the religious community about whether the license plate is appropriate or not. No way to tell.
Or maybe my alternate explanation covers it: The car actually belongs to a former Muslim, who is questioning the faithful by asking, "Why Allah?"
It just reinforces my tendency to think that license plates are a poor way to communicate clearly. Better to cover your car with bumper stickers so everyone can be sure about what you think.