A plan to widen Fairfax County Parkway between Route 50 and the Dulles Toll Road is without funding or a definite timeline, though officials speak optimistically about the project’s eventual completion.

The widening would add two lanes to the 6.5-mile stretch of highway, and is projected to cost $100 million, said Keith Foxx, project manager with the Fairfax County Department of Public Works and Environmental Services. The project, which could include an additional HOV lane, is included in the county’s transportation plan update.