(2) An underground assessment district shall include an area having a frontage of not less than 400 feet upon a public street, road or highway along which overhead electric or communication facilities are located.
(3) An underground assessment district:
(a) Created by a city, may include area along city streets, county roads and state highways or any part thereof located within the district.
(b) Created by a county, may include areas along county roads, state highways or any part thereof located within the district. [1969 c.385 §3]