Characters in Vehicles

A character in a vehicle fills one of several possible roles, which determines what the character can do.
Driver: The driver of the vehicle controls its movement. Most vehicles have only one position from where the vehicle can be driven, so the person seated there is the driver. Driving a vehicle is, at a minimum, a move action, which means that the driver may be able to do something else with his or her attack action. There can be only one driver in a vehicle at one time.
Copilot: A copilot can help the driver by taking an aid another action. The copilot must be seated in a location where he or she can see the road and advise the driver (in a car, this generally means the front passenger seat). Aiding the driver is a move action, leaving the copilot with an attack action each round to do something else. A vehicle can have only one copilot at a time. A copilot can also drive the vehicle if the driver cannot or chooses not to, provided there is a second set of controls at the copilot's seat (usually true in aircraft, but not ground vehicles).
Gunner: Some vehicles have built-in weapons. If such a weapon is controlled from a location other than the driver's position, a character can man that position and become the gunner. A vehicle can have as many gunners as it has gunner positions.
Passenger: All other personnel aboard the vehicle are considered passengers. Passengers have no specific role in the vehicle's operation, but may be able to fire weapons from the vehicle or take other actions.