The boards may expend funds credited to the county road fund from any county or road district tax levied for the construction of county roads for the construction of sidewalks, bicycle paths, lanes, routes, and roadways, and pedestrian allocated paths or walks. Bicycle facilities constructed or modified after June 10, 1982, shall meet or exceed the standards of the state department of transportation.
RCW 36.75.240
Pavement marking standards: RCW 47.36.280.