Only a few more days left to take this online survey - last day is Nov. 9:

https://www.surveymonkey.com/r/tppfunding

One of the survey questions asks which two bicycling-specific projects you want the most. The other questions include a transit project question and the rest I think are car/road related.

There is a link on the survey page to the main "Fairfax County Transportation Priorities Plan Update 2017" page.