The location of all pipes, hydrants, wires and cables and all conduits and other structures for the conducting and maintaining of those pipes, hydrants, wires and cables over, under the surface of and in those streets and highways in which those utilities authorized to obtain locations for their pipes, wires, hydrants and cables which have been located over, under the surface of and in the streets and highways prior to January 1, 1984, and which will be so located in accordance with this Title are declared legal and the same shall be legal structures in those streets and highways until their location has changed in any manner required or authorized by law. [PL 1987, c. 141, Pt. A, §6 (NEW).]