N.C. Gen. Stat. § 20-317

This Article shall not be held to apply to or affect policies of automobile insurance against liability which may now or hereafter be required by any other law of this State, and such policies, if they contain an agreement or are endorsed to conform to the requirements of this Article, may be certified as proof of financial responsibility under this Article. This Article applies to vehicles of motor carriers required to register with the Division under G.S. 20-382 or G.S. 20-382.1 only to the extent that the amount of financial responsibility required by this Article exceeds the amount required by the United States Department of Transportation.