Massachusetts General Laws Part I. Administration of the Government (Ch. 1-182) Ch. 90, § 19G

A motor vehicle authorized to operate on the National Network under the provisions of section nineteen F, and which is not authorized by section nineteen to operate without permit on ways within the commonwealth, may be authorized to operate on routes of reasonable access, as defined in section one, as follows:

the operator of any terminal, or the owner, lessee or operator of any vehicle, may request in writing to the department a specific route of reasonable access. Such requested route of reasonable access shall be deemed approved by the department if the department does not disapprove it in writing and for specific reasons of safety within ninety days of receipt of said request. Although a requested route may be established, it shall remain subject to disapproval or alteration in writing by the department at any time for specific safety reasons. A conclusive safety evaluation of a requested route shall be based on the application of templates to the route configurations for purposes of determining if such route is capable of safely accommodating the operating characteristics of the particular type of vehicle or, where a statistical record has been established, may be based on verifiable accident frequency.