I think most of you guys are wrong.
Personaly, i believe that at the end, the taxi driver is the angel of death (the grim reaper).
Remember there mention of the myth? The god who cheated death and was doomed to repeat a task?
Well. At the end, i believe she dies in the car crash, when the driver offers to "keep the meter running" and she responds with "yes, i promise to come back" she i cheating death- she doesnt return, and has lied to the reaper. Therefor, like in the myth, she repeats what she has done."