Final answer:
Emergency crossovers on the interstate in Tennessee are legal for the purpose of allowing emergency vehicles and highway maintenance crews to make necessary turns or access areas, such as for responding to emergencies or performing maintenance on the highways.
Step-by-step explanation:
Emergency crossovers on the interstate are legal in Tennessee for specific, limited purposes. They are not intended for regular traffic maneuvers like making a U-Turn when you miss your exit or simply turning around when no other vehicles are present. Instead, these crossovers are legally designated for use by emergency vehicles and highway maintenance crews only. These protocols are put in place to ensure safety on the interstates, as emergency crossovers can present hazards if used improperly by the general public.