Section 7C. No financial assistance shall be provided by the commonwealth for the purchase of buses or the operation thereof to any applicant for such assistance unless such applicant and the secretary of transportation and construction shall have first entered into an agreement that such applicant will not engage in school bus operations, exclusively for the transportation of students and school personnel, in competition with private school bus operators. This section shall not apply to an applicant with respect to operation of a school bus program if the applicant operates a school system in the area to be served and operates a separate and exclusive school bus program for this school system. This section shall not apply unless private school bus operators are able to provide adequate transportation at reasonable rates, and in conformance with applicable safety standards.