The cabin or cab of a truck is the inside space in a truck where the driver is seated. Modern long-haul (long distance) trucks cabs usually feature air conditioning, a good sound system, and ergonomic seats (often air-suspended). Pickup truck cabs have options that can make them as comfortable to drive as a car. Regular cab means a pickup truck with 2 doors. It has a single row of seating and may seat one or two passengers. Extended cab means a cab with rear seating. It can have two, three or four doors. Crew Cab means a 4-door truck cab. Is sometimes called a double cab.