In 1974, in response to a request from the DOT, the General Services Administration (GSA) developed the "KKK-A-1822 Federal Specifications for Ambulances". The act defined the following basic types of ambulance:
Type I - conventional cab and chassis on which a module ambulance body is mounted, with no passageway between the driver and patient's compartments
Type II - A standard van, body, and cab form an integral unit. Most have a raised roof.
Type III - This is a specialty van with forward cab and integral body. It has a passageway from the driver's compartment to the patient's compartment.