What are the three forms of national and provincial trunk highway management system

Hey, just asked about a training on a while ago.

At present, there are four types of ordinary national and provincial trunk highway management mode. Simply summarize the following is:

1, the provincial highway department directly on the provincial national and provincial trunk highway management.

2, the provincial level is responsible for industry supervision, the national and provincial trunk highway management authority down to the municipal level, by the municipalities responsible for the specific management.

3, the provincial and municipal levels responsible for industry supervision, decentralized to the district and county highway agency management.

4, there is a kind of province is mixed, both decentralized to the management of municipalities, there are also decentralized to the management of districts and counties.