75 Pa. C.S. § 6143
The secretary may enter into an agreement or arrangement with the duly authorized representatives of other jurisdictions, granting to drivers or vehicles or owners of vehicles properly licensed or registered in those jurisdictions, and for which evidence of compliance is supplied, benefits, privileges and exemptions from the payment, wholly or partially, of any taxes, fees or other charges imposed upon the drivers, vehicles or owners with respect to the operation or ownership of the vehicles under the laws of this Commonwealth. The agreement or arrangement shall provide that drivers or vehicles properly licensed or registered in this Commonwealth, when operating upon highways of the other jurisdiction, shall receive exemptions, benefits and privileges of a similar kind or to a similar degree as are extended to drivers or vehicles properly licensed or registered in the jurisdiction when operating in this Commonwealth. Each agreement or arrangement shall, in the judgment of the secretary, be in the best interest of this Commonwealth and the citizens thereof and 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.
75 Pa.C.S. § 6143