Type D School Buses Type "D" school buses, which are also frequently referred to as "Transit", "Forward Control", or "FC", are higly manuverable buses which offer incresed visibility to the school bus driver.  The largest buses, 83 passenger and 89 pasenger configurations, are Type "D" buses.   A "type D school bus" is a body installed upon a chassis, with the engine mounted in the front, midship or rear, with a gross vehicle weight rating of more than 10,000 pounds, designed for carrying more than ten persons.  The engine may be behind the windshield and beside the driver's seat; it may be at the rear of the bus, behind the rear wheels, or midship between the front and rear axles.  The entrance door is ahead of the front wheels.  A type D school bus has a maximum length of 45 feet.