At the 13th National School Transportation Conference in May 2000, conferees revised the GVWR ratings for Type A-I and A-II school buses. Previously, Style A-II was the smaller bus with a GVWR of 10,000 lbs. or less, while the Style A-I had a GVWR of 10,001 lbs. or more. The revised designations adopted at the conference reverse the weight ratings. Style A-I is now the smaller bus, while Style A-II has the greater GVWR.

A conversion or body constructed upon a van-type compact truck or a front-section vehicle (cutaway), designed for carrying eight (8) to twenty-four (24) persons, and having a GVWR of 10,000 lbs. or less.

Like a Style A-I, but constructed on a heavy duty chassis with a Gross Vehicle Weight Rating of 10,001 lbs. or greater. Because of the chassis, the useful and economic lifespan of a Style A-1I is usually greater than that of a Style A-I school bus.

A conversion or body constructed and installed upon a van or front-section vehicle chassis, or stripped chassis, designed for carrying between eighteen (18) and thirty-two (32) 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.

A body installed upon a flat back cowl chassis, designed for carrying between thirty (30) and seventy-two (72) persons. All of the engine is in front of the windshield and the entrance door is behind the front wheels.

A body installed upon a chassis, with the engine mounted in the front, midship, or rear, designed for carrying more than fifty-four (54) 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 it may be located midship between the front and rear axles. The entrance door is ahead of the front wheels.