The U.S. Federal Claims Court has unhitched a utility's claim to the “mobile machinery exemption” because it had pintle hooks on its vehicles (Florida Power & Light v. U.S.). The utility said trucks equipped for off-road servicing of transmission equipment were modified to serve only as mounts and carriages for operating off-road, thus qualifying for an exemption from the heavy-vehicle use tax. The IRS said the addition of a pintle hook for hauling trailers with supplies and equipment made the vehicles into highway tractors. The court sided with the IRS.