The Fairfax County Board of Supervisors will vote on the county's participation in Phase Two of a multi-billion project to extend Metrorail through Tysons Corner to Dulles Airport.
The project will cost an estimated $2.7 billion and extend the line to Dulles and eastern Loudoun.
The outgoing county executive is recommending the board confirm its participation in the project, while remaining vigilant in its pursuit of more funding.
Phase Two would rely heavily on increased tolls on the Dulles Toll Road. Projections show one-way tolls could triple to $6.75 by 2018.
Phase One, which runs through Tysons to Reston, is more than halfway complete and is scheduled for completion by the end of 2013.
The board will also vote on the approval of recommended station names.