Jseis 

Separated MUP development is often the most desirable but cost prohibitive due to right of way acquisition/litigation and environmental review, thus the use of old railroad grades (via federal rail banking laws) because of the existence of the right of way/corridor and ballast to support trains. However, always controversy (Burke Gilman Trail in Seattle). There is nothing more lonely than going to a public hearing as a project proponent/planner on a trail or trail plan and have not a single cyclist show up. (BTW..an MUP is essentially built to a one land road standard and on its own right of way or using part of an existing right of way like an old railroad or unused roadway. What makes new MUP's costly are cuts/fills/bridges grade/slope and etc because they are bicycle highways. The term "trail" softens the blow but imagine dealing with a railroad grade and all the crossings, steel bridges, remote locations...not easy).

Cyclists who think road or trail improvements magically appear need to reassess that view because any significant MUP extension/new construction or highway bike lane improvement takes years of planning and foresight. Organizations such as the Cascade Bicycle Club (Seattle based but has cycling programs statewide) can and will play a role in gaining improvements because their 14,000 members are organized. The single best thing you can do is become a member of bike club...locally and regionally.