Miss. Code Ann. § 27-19-29: Miss. Code Ann. § 27-19-29

No tax shall be levied under the provisions of this article upon any tractor, road roller or road machinery used solely and exclusively in road building or other highway construction or maintenance work or upon vehicles permanently equipped with and used exclusively for transporting water well drilling outfits, all of which vehicles are not used upon the highways of this state for the transportation of persons or property.