"Who is driving the car?"
Translation:Arabayı kim kullanıyor?
The word order depends on the emphasis as AlexinNotTurkey notes below. Another example is where you put interrogative "mi": it comes just before the emphasised word. For example, "Is DUO (not someone else) going to Turkey ?" = "Duo mu Turkiye'ye gidiyor ?", but "Is Duo going to TURKEY (not to anywhere else) ?" = "Duo Turkiye'ye mi gidiyor ?".