(1) The department shall compile statistics regarding public highways throughout the state and collect all related information deemed expedient.
(2) It shall investigate various methods of construction adapted to different sections of the state and decide the best methods of construction and maintenance of highways, bridges, and road markers.
(3) The department may be consulted at all reasonable times by county officers having care and authority over highways and bridges and shall advise them on construction, repair, alteration, or maintenance.
(4) The department shall furnish such information and advice as may be requested by persons interested in the construction, maintenance, and marking of public highways. It shall at all times lend its aid in promoting highway improvement throughout the state.