A recreational vehicle, a vehicle displaying restricted plates, or a government-owned vehicle, are not apportionable vehicles; except that a truck or truck tractor, or the power unit in a combination of vehicles having a GVW of 26,000 pounds (11,793.401 kilograms) or less, never the less, may be registered under the Plan at the option of the registrant.
29- 250 C.M.R. ch. 162, § 1