When considering new vehicle purchases, program directors should understand the four basic types of buses available. Manufacturers can configure each of the four types as either a traditional school bus or as an allowable alternate vehicle (AAV). This tip sheet provides a brief description of each type.

Type A-1 and A-11

A conversion or body constructed on a van-type or cutaway front-section vehicle with a left-side driver's door, designed for carrying more than 10 persons. This definition includes two classifications: Type A-1, with a gross vehicle weight rating (GVWR) of 10,001 lbs. or more; and Type A-11, with a GVWR of 10,000 lbs. or less.

Type B

A conversion or body constructed on a van or front-section vehicle chassis or stripped chassis with a GVWR of more than 10,000 lbs. designed to carry more than 10 persons. Part of the engine is beneath and/or behind the windshield and beside the driver's seat. The entrance door is behind the front wheels.

Type C

A body installed on a flat-back cowl chassis with a GVWR of more than 10,000 lbs. designed to carry more than 10 persons. The engine is in front of the windshield and the entrance door is behind the front wheels.

Type D

A body installed upon a chassis with the engine mounted in the front, midship or rear and a GVWR of more than 10,000 lbs. designed to carry more than 10 persons. The engine may be behind the windshield and beside the driver's seat, 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.