66 Pa.C.S. § 307

The commission may employ such inspectors, as it may deem necessary, for the purpose of enforcing the provisions of this part. Such inspectors are hereby declared to be police officers, and are hereby given police power and authority throughout this Commonwealth to arrest on view, without writ, rule, order, or process, any person operating as a motor carrier or common carrier by airplane without a certificate or permit required by this part. Such inspectors are hereby given authority to stop vehicles on the highways of this Commonwealth, and to inspect the cargoes of such vehicles, and any receipts or bills of lading pertaining to such cargoes.