In which period and area? Chariots saw heavy use in many cultures and periods. In ancient China for example chariots were commonly crewed by three: Driver, spearman/axeman, and archer. I would suspect different chariot sizes and tactics would dictate different crews, but I can't imagine someone both driving a chariot and being an effective archer simultaneously (implying you need a crew of 2+ to have an archer).

As a source on China I recall discussion of this on a translation of Sun Zu's Art of War (can't recall which one off hand but can dig it up if needed) but I also found this article about three man crews in the Shang Dynasty.