74 Pa. Stat. § 106
On and after the grant and conveyance aforesaid, and upon the acceptance of the same by the United States of America, the exclusive jurisdiction over the highway herein established is hereby ceded to the United States of America by the Commonwealth of Pennsylvania: Provided, That this cession is made upon the express condition that the Commonwealth of Pennsylvania so far retains concurrent jurisdiction with the United States over said highway as that all civil and criminal process issued under the authority of this Commonwealth may be executed thereon in like manner as if this cession had not been made: And provided further, That all offenses against the criminal laws of Pennsylvania, committed upon said highway, shall remain, as before cognizable in the courts of this Commonwealth; but nothing herein contained shall in any wise interfere with the right and power and jurisdiction of the United States to enact and enforce laws for the protection of said highway, and for the protection and comfort of travelers on said highway, and for insuring unto the President of the United States, his family, his officers and agents, and his guests, free and unobstructed and safe passage over and along said highway.
74 P.S. § 106