75 Pa.C.S. § 6147

In the absence of an agreement or arrangement with another jurisdiction, the secretary may examine the laws and requirements of such jurisdiction and declare the extent and nature of exemptions, benefits and privileges to be extended to vehicles properly registered or licensed in the other jurisdiction, or to the owners of the vehicles, which shall, in the judgment of the secretary, be in the best interest of this Commonwealth and the citizens thereof, and which shall be fair and equitable to this Commonwealth and the citizens thereof, and shall be determined on the basis and recognition of the benefits which accrue to the economy of this Commonwealth from the uninterrupted flow of commerce.