Massachusetts General Laws Part I. Administration of the Government (Ch. 1-182) Ch. 90, § 7D

The requirements of clauses (1), (2), (3), (5), (7), (8), (9), (10), (13) and (16) of section seven B shall apply to any motor vehicle carrying not more than eight passengers in addition to the operator, used in the business of transporting school pupils for hire under terms of contract or otherwise, while so used, but not including any motor vehicle used for not more than five days in case of emergency; provided, however, the eight lamp system, so-called, required on certain motor vehicles in clause (7) of said section seven B shall not apply to vehicles specified in this section. In addition, each such vehicle shall be required to be equipped with one pair of adequate chock blocks, a fire extinguisher, three flares in compliance with United States Motor Vehicle D.O.T. Safety Standard No. 125, which shall be placed upon the roadway in conformance with section fourteen B of chapter eighty-five when such vehicle becomes disabled upon the traveled portion of any way, and seat belts for each permanent seating accommodation designed and installed in compliance with applicable United States Motor Vehicle Safety Standards. No person shall operate a motor vehicle referred to in this section, nor knowingly allow any passenger to ride in such vehicle unless the operator and all passengers are wearing a safety belt which is properly adjusted and fastened. All such motor vehicles used to transport school pupils under the provisions of this section shall display the distinctive number plate as authorized by section two.

The provisions of this section, excluding the seatbelt requirement, shall not apply to the transportation of school pupils in vehicles not exceeding fourteen passengers in addition to the operator which is provided (a) by an operator who is uncompensated for his or her service and is either a parent and one adult (monitor) of one of the passengers or is a person chosen by the parents of all the passengers; or (b) for activities related to a private school, child care center, camp, school-age child care program, or a special needs program as defined by section one of chapter seventy-one B, who would not be picked up or discharged on a fixed route, provided, that for the purpose of this section, the term fixed route shall be defined as the transportation of a school pupil on a pre-determined daily basis to and from a set location, for the length of the pupils school year, provided the operator is a person whose primary relationship to the passenger is that of teacher, coach, director, or caregiver, and not as an operator. Such vehicles shall not be considered school buses, school pupil transport vehicles or livery vehicles and shall be registered as private passenger motor vehicles.