In preparing their respective six-year programs relating to rural arterial improvements, counties shall select specific priority improvement projects for each functional class of arterial based on the rating of each arterial section proposed to be improved in relation to other arterial sections within the same functional class, taking into account the following:
The six-year construction programs shall remain flexible and subject to annual revision as provided in RCW 36.81.121.
RCW 36.79.080