66 Pa.C.S. § 313

(a) Joint hearings and investigations.--The commission shall have full power and authority to make joint investigations, hold joint hearings within or without this Commonwealth, and issue joint or concurrent orders in conjunction or concurrence with any official, board, commission, or agency of any state or of the United States, whether in the holding of such investigations or hearings, or in the making of such orders, the commission shall function under agreements or compacts between states or under the concurrent power of states to regulate the interstate commerce, or as an agency of the Federal Government, or otherwise.

(b) Reciprocity.--The commission shall have full power and authority to arrange reciprocity of treatment of public utilities and contract carriers by motor vehicle of this Commonwealth by regulatory bodies, under regulatory laws of other states, and to that end the commission is hereby vested with power to impose upon public utilities and contract carriers by motor vehicle of other states, the same penalties, restrictions, and regulations as are imposed by the regulatory body of such other states upon public utilities and contract carriers by motor vehicle of this Commonwealth when operating into, out of, or through such other states.