1. (a) Article 21 of the Tax Law contains a definition of “motor vehicle” which differs from the ordinary definition. The term motor vehicle is defined to mean:

   1. (1) any self-propelled device and any trailer or other device drawn thereby used upon the public highways having a maximum gross weight, alone or in combination with another motor vehicle, in excess of 18,000 pounds;
   2. (2) any truck having an unloaded weight in excess of 8,000 pounds;
   3. (3) any tractor having an unloaded weight in excess of 4,000 pounds (for definition of maximum gross weight and unloaded weight, see section 472.1 et. seq.); and
   4. (4) any omnibus engaged in the interstate or foreign transportation of passengers and subject to the jurisdiction of the Interstate Commerce Commission, or any agency successor thereto, or one or more State regulatory agencies concerned with the regulations of passenger transport, having a seating capacity of more than seven persons in addition to the driver.

2. (b) The following vehicles are not motor vehicles under this definition:

   1. (1) truck with an unloaded weight of 8,000 pounds or less and a maximum gross weight of 18,000 pounds or less;
   2. (2) tractor with an unloaded weight of 4,000 pounds or less and a maximum gross weight of 18,000 pounds or less;

   3. (3) trailer, semi-trailer, dolly, or other device drawn by a motor vehicle, with a maximum gross weight, alone or in combination with another motor vehicle, of 18,000 pounds or less.

      In this Subchapter, the term motor vehicle will be used as defined in subdivision (a) of this section.

      Example 1:

      A tractor having an unloaded weight of 3,500 pounds, but a maximum gross weight of 19,000 pounds when used in combination with a trailer, is a motor vehicle.

      Example 2:

      A semi-trailer having an unloaded weight of 10,000 pounds, but a maximum gross weight of 49,000 pounds when used in combination with a tractor, is a motor vehicle.

      Example 3:

      A truck having an unloaded weight of 8,500 pounds and a maximum gross weight of 16,000 pounds is a motor vehicle.

      Example 4:

      A tractor having an unloaded weight of 5,000 pounds and a maximum gross weight of 15,000 pounds, when used in combination with a trailer, is a motor vehicle.

3. (c) A tow truck pulling a disabled motor vehicle is not deemed to be operating in combination with such motor vehicle. Therefore, if the unloaded weight of the tow truck is 8,000 pounds or less, it is not a motor vehicle. However, if the unloaded weight of the tow truck exceeds 8,000 pounds, it is a motor vehicle.

   Example 1:

   A tow truck, having an unloaded weight of 20,000 pounds pulls a disabled snow plow weighing 35,000 pounds; the tow truck is a motor vehicle.

   Example 2:

   A tow truck having an unloaded weight of 7,000 pounds pulls a disabled truck weighing 18,500 pounds; the tow truck is not a motor vehicle.

Tax Law, §§ 501(2) 503-a(9)