Local authority shall mean every county, municipal, and other local board or body having power to enact laws, rules, or regulations relating to traffic under the Constitution of Nebraska and the laws of this state and generally including the directors of state institutions, the Game and Parks Commission, and all natural resources districts with regard to roads not a part of the state highway system and within the limits of such institution, of an area under Game and Parks Commission control, or of an area owned or leased by a natural resources district, but outside the limits of any incorporated city or village.