Tank
Most modern tanks most often have four crew members, or three if an auto-loader is installed. These are the:
Historically, crews have varied from just two members to a dozen. For example, pre-World War II French tanks were noted for having a two-man crew, in which the overworked commander had to load and fire the gun in addition to commanding the tank. First World War tanks were developed with immature technologies; in addition to the crew needed to man the multiple guns and machine guns, up to four crewmen were needed to drive the tank: the driver, acting as the vehicle commander and manning the brakes, drove via orders to his gears-men; a co-driver operated the gearbox and throttle; and two gears-men, one on each track, steered by setting one side or the other to idle, allowing the track on the other side to slew the tank to one side.
Hammerverse
The tanks are supported by smaller "combat cars", armored air cushion vehicles that mount three 2 cm tribarrels. Combat cars have a crew of one driver, one vehicle commander who doubles as a gunner, and two wing gunners. The armor, sensors, redundancy, and artificial intelligence of the combat cars are not as extensive as those on the tanks. The combat car was inspired by Drake's recollection of the "ACAV" version of the M113 Armored Personnel Carrier. A command version of the standard combat car, essentially a steel box on a combat car chassis, exists. The command car's powerful computer and communications gear is useful for unit commanders, although many commanders choose instead to use a standard combat car as their command vehicle.