This has been in the works for some time, but now it’s official: the Metropolitan Washington Airports Authority Board of Directors unanimously approved a plan today to raise rates on the Dulles Toll Road, WTOP’s Adam Tuss reports. Starting Jan. 1, the toll at the main gate will increase from 75 cents to $1, while tolls at the off ramps will go up from 50 to 75 cents. Tolls will increase an additional 25 cents in 2011, and again in 2012. Revenue from the toll increase will go toward building the Silver Line.