Since news broke that 3 Northern Virginia county parkways were getting new state route numbers, Google has already updated their maps for two of them. First, the Prince William Parkway and its new route 294 was updated. As of this morning, the Franconia-Springfield Parkway is now shown with primary Virginia state route 289.
Oddly, Google Maps never used a secondary route 7900 marker, just text.
I am still keeping my eye on Fairfax County Parkway for route 286 signs.
UPDATE: The new route number has been removed by Google Maps as of March 3, 2012
Sign: Shields Up!