A. If the streets of an incorporated city or town form necessary or convenient links for the connection of sections of state highways or state routes, or for carrying the state highways or state routes through the city or town, the director and the governing body of the city or town, in the case of state highways, or the board of supervisors and the governing body of the city or town, in the case of state routes, may agree that the streets are deemed state highways or county highways, respectively.

B. The agreement shall provide for maintenance of the streets classified pursuant to this section.