The New Zealand state highway network is the major national highway network in New Zealand. Nearly 100 roads in the North and South Islands are state highways. All state highways are administered by the NZ Transport Agency. Of the total state highway network, New Zealand currently has 363 km (226 mi) of motorways and expressways with grade-separated access and they carry ten percent of all New Zealand traffic. The majority of the state highway network is made up of single-carriageway roads with one lane each way and at-grade access.