Film Details:
Here is more information about the costume and how it informs the character:
Dark, brooding, everyman Travis Bickle wants to wipe the scum from New York City. This disillusioned ex-Marine and Vietnam veteran spends his nights driving a cab and spends his days frequenting adult theatres and reflects on the cesspool that is humanity. Upon first glance, Bob's relatively nondescript wardrobe as Travis underscores his argument that he is an overlooked man in an uncaring society.
Did you know? Bob, the method actor that he is, actually trained to be a New York City cab driver and earned his licence.