Here are the materials in State v. Kostick (N.C. App.):
Pursuant to the Tribal Code of the Eastern Band of the Cherokee Indians and mutual compact agreements between the Tribe and other law enforcement agencies, the North Carolina Highway Patrol has authority to patrol and enforce the motor vehicle laws of North Carolina within the Qualla boundary of the Tribe, including authority to arrest non-Indians who commit criminal offenses on the Cherokee reservation. Our State courts have jurisdiction over the criminal offense of driving while impaired committed by a non-Indian, even where the offense and subsequent arrest occur within the Qualla boundary of the Cherokee reservation.