The legislative authority of each county may by resolution classify and designate portions of the county roads as primitive roads where the designated road portion:

(1) Is not classified as part of the county primary road system, as provided for in RCW 36.86.070;

(2) Has a gravel or earth driving surface; and

(3) Has an average annual daily traffic of one hundred or fewer vehicles.

Any road designated as a primitive road shall be marked with signs indicating that it is a primitive road, as provided in the manual of uniform traffic control devices, at all places where the primitive road portion begins or connects with a highway other than another primitive road. No design or signing or maintenance standards or requirements, other than the requirement that warning signs be placed as provided in this section, apply to primitive roads.

The design of a primitive road, any discretionary maintenance, and the location, placing, or failing to place road signs, other than the requirement that warning signs be placed as provided in this section, shall not be considered in any action for damages brought against a county, or against a county employee or county employees, or both, arising from vehicular traffic on the primitive road.