Mass. Gen. Laws ch. 159B § 14A
Every motor carrier, including private carriers and interstate licensees, their agents and employees, when requested by a duly authorized state police officer who is in uniform or displays the proper insignia of his office, shall stop and submit to said duly authorized state police officer all transportation documents, including bills of lading, way bills and other papers relating to his cargo which are in his possession and shall submit the cargo and other contents, if any, of his motor vehicle to such reasonable examination as may be necessary to inform the duly authorized state police officer of the nature and the weight thereof. No detail examination of the cargo shall be made that requires the removal of the cargo from the vehicle except at a place where the motor vehicle stops for the purpose of loading or delivery, and such motor vehicle may be required to detour to the nearest available scale within a distance of not more than five miles for the purpose of determining the weight thereof. Any such carrier who, personally or by his agent, or any such driver who violates any provision of this section, shall be punished by a fine of not less than two hundred and fifty nor more than five hundred dollars for the first offense and not less than five hundred nor more than one thousand dollars for subsequent offenses.
Mass. Gen. Laws ch. 159B, § 14A