§ 308. Definitions. As used in this article the term "motor vehicle"
shall include trailers and all vehicles included in the definition of
the term "motor vehicle" contained in section one hundred twenty-five of
this chapter except the following:

1. Road rollers, tractor cranes, truck cranes, power shovels, road
building machines, snow plows, road sweepers, sand spreaders, well
drillers, well servicing rigs, feed processing machines, mobile car
crushers, earth movers, trucks with small wheels used in a factory,
warehouse or railroad station, agricultural spreaders and sprayers, or a
tractor-trailer combination designed and used exclusively for the same
purpose as a vehicle specifically included in the foregoing, or

2. Vehicles inspected by or operating under a certificate of
inspection authorized by the commissioner of transportation or the
interstate commerce commission, or of a municipally owned and operated
transit system, or

3. Farm vehicles registered under subdivision thirteen of section four
hundred one of this chapter, self-propelled combines, self-propelled
corn and hay harvesting machines and tractors used exclusively for
agricultural purposes, or

4. Vehicles subject to inspection and licensing by local authorities
provided such inspection by such local authorities conforms with the
standards established by the commissioner under this article, or

5. Fire vehicles, except ambulances; or

6. Police vehicles for which the department operating such vehicles
has submitted a plan approved by the commissioner, who shall establish
the standards therefor, for periodic inspection thereof. Such plans
shall be submitted to the commissioner by September thirtieth of each
year. In determining the acceptability of such inspection plans and in
establishing standards therefor, the commissioner shall require that
such periodic inspections shall be substantially equivalent to
inspections required for other motor vehicles under this article and
shall be made with respect to such mechanisms and equipment as shall be
determined by the commissioner to be necessary for the proper and safe
operation of such vehicles.