(1) The provisions of this chapter must be applicable and uniform throughout this state and in all political subdivisions and municipalities in this state, and a local authority may not enact or enforce any ordinance, rule, or regulation in conflict with the provisions of this chapter unless expressly authorized in this chapter. Local authorities may adopt additional traffic regulations that are not in conflict with the provisions of this chapter.
(2) As used in this section "local authorities" has the meaning provided in 61-8-102.