Massachusetts General Laws Part III. Courts, Judicial Officers and Proceedings in Civil Cases (Ch. 211-262) Ch. 262, § 10

If it is necessary in the service of civil process for an officer to use a conveyance for a distance exceeding two miles one way, he may be allowed therefor fifteen cents a mile for the distance traveled, not exceeding thirty miles. If he uses the conveyance of another person he shall be allowed the amount actually expended by him therefor; but no allowance for the actual amount so expended by him shall be made unless the officer certifies that it was necessary for him to use a conveyance, and that he actually used it for the distance, and paid therefor the amount stated in his certificate.