(1) The secretary of transportation may install and maintain traffic control devices upon state-maintained highways in such manner as is reasonably necessary to promote the safety and convenience of the traveling public.
(2) The driver of any vehicle shall obey the instructions of any official traffic control device applicable thereto unless otherwise directed by a traffic or police officer, subject to the exceptions granted the driver of an authorized emergency vehicle.
(3) The secretary of transportation may restrict or regulate traffic upon state-maintained highways in such a manner as is reasonably necessary to promote the safety of the traveling public.