Types of Buses
What kind of buses and vehicle are there? This page describes the official types of buses and vans available.
School Bus Classification
A Type “A” school bus is a van conversion or bus constructed utilizing a cutaway front section vehicle with a left-side driver's door. ... The entrance door is behind the front wheels.
A Type B school bus shall mean a conversion or body constructed and installed upon a van or front section vehicle chassis, or stripped chassis, with a GVWR greater than 10,000 pounds, designed for carrying more than ten persons.
A Type C school bus shall mean a body installed upon a flat back cowl chassis, or a stripped chassis, with a GVWR greater than 21,500 pounds, designed for carrying more than ten persons. ... This type also includes the above chassis with a passenger seating capacity greater than 36, and may have a left side driver's door.
The Type D, or “transit-style” school bus, is a body installed upon a chassis, with the engine mounted in the front, mid-ship, or rear with a gross vehicle weight rating of more than 10.000 pounds, and designed for carrying more than 10 persons. The engine is often behind the windshield and beside the driver’s seat (referred to as forward-engine or “FE”), or it may be at the rear of the bus, behind the rear wheels (rear-engine or “RE”). The entrance door is ahead of the front wheels.
Intercity coaches are the buses used by companies like Greyhound or Trailways transporting people long distances. With few exceptions these buses are built with a diesel pusher that can be found in class 8 trucks. Since the early 1960s all are built with an air ride suspension system. Manufacturers of coaches include MCI, Flxible, Eagle, and Prevost.
Coaches can mostly be found in 35, 40, and 45 foot lengths. 40 and 45 foot buses will have a tag axle to help support the extra weight. This axle is not driven and can usually be raised and lowered to help with traction when needed. Coaches are also available in 96 or 102 inch widths. 102 inch buses are only available on newer buses from after laws were changed to allow them (with the exception of the MCI MC6).
Coaches are mostly built with a weight saving "Air Frame" style construction where there are no frame rails and the structure of the body and outer skin are integral to the frame of the vehicle. Generally the outer skin will be stainless steel or aluminum and the inner framework will be mild steel. Severe rust on the inner framework can cause a structural failure of the vehicle.
Many coaches are converted after they are sold off from service. Generally the bus will have a few million miles on it at this point and will be judged more on how it was maintained than mileage as its first engine will be long gone along with many drivetrain components. Others can be found that were bought new with no interior and built as an RV. These are the most sought after due to the low mileage and professional conversion.
An airport bus, or airport shuttle bus or airport shuttle is a bus used to transport people to and from, or within airports. These vehicles will usually be equipped with larger luggage space, and incorporate special branding.  They are also commonly used as smaller inner-city transit as well as hotel shuttles. Typically they are larger than a Class A (Short bus skoolie) with a taller roof with interior height being 6'3 to 6'6 and slightly longer body. The shells are also generally fiberglass whereas a Class A is steel.
<Other vehicles info>
(Brief summary, there's a dedicated page for Other Vehicles.)
See Other Vehicles for more info.