§ 906. Police service agreements. A municipality or the Pennsylvania State Police may enter into cooperative police service agreements with the National Park Service for the purpose of providing employees of the National Park Service who hold a valid law enforcement commission, issued by that agency, the authority to enforce Title 75 (relating to vehicles) on roads, other than Federal roads, which lie within units of the National Park System which are within the jurisdiction of the municipality's police department or the Pennsylvania State Police.