The annual revision and extension of comprehensive road programs pursuant to RCW 36.81.121 shall include consideration of and, wherever reasonably practicable, provisions for bicycle paths, lanes, routes, and roadways: PROVIDED, That no provision need be made for such a path, lane, route, or roadway where the cost of establishing it would be excessively disproportionate to the need or probable use.
RCW 36.81.122