Massachusetts General Laws Part I. Administration of the Government (Ch. 1-182) Ch. 84, § 16

If a person, without the consent of the county, city, town or person required by law to keep a bridge in repair or his or its agent, permits more than twenty neat cattle or horses to be upon a bridge which is more than fifty feet from one abutment, pier or trestle part to another, or drives or transports over such bridge a vehicle with a load exceeding forty-five hundred pounds in weight exclusive of the team and vehicle, and thereby breaks or injures the bridge, such county, city, town or person shall not be liable for any damage caused thereby.