(1) Motor carriers are divided into three classes to be known as:
(a) Class A motor carriers;
(b) Class D motor carriers; and
(c) Class E motor carriers.
(2) Class A motor carriers include all motor carriers operating between fixed termini or over a regular route and under regular rates or charges, based upon either station-to-station rates or upon a mileage rate or scale.
(3) Class D motor carriers include all motor carriers operating motor vehicles transporting garbage.
(4) Class E motor carriers include all transportation network carriers.