(a) The provisions of this chapter applicable to the drivers of vehicles upon the highways shall apply to the drivers of all vehicles owned or operated by the United States, this state, or any county, city, town, district, or any other political subdivision of the state, except as provided in this section and subject to such specific exceptions as are set forth in this chapter with reference to authorized emergency vehicles.
(b) Unless specifically made applicable, the provisions of this chapter shall not apply to persons, teams, motor vehicles, and other equipment while actually engaged in work upon the surface of a highway but shall apply to such persons and vehicles when traveling to or from such work.