Yes, but never underestimate the power of trying to do any construction in the bizarro world known as Washington, DC. The way land values go up there, that $2.4B could end up being $24B in an eyeblink!
Actually I'm torn on this...the DC suburbs sprawl so badly that they've totally outstripped the ability to access Metro, considering that Metro barely extends outside the Beltway and the biggest growth areas are 20+ miles away. But then, how many of the people who live in places like Herndon and Reston and Vienna and Chantilly and beyond are actually going all the way into DC to work, and how many are working in Tysons and Herndon, where Metro will do them no good?
}:-)4
In Maryland, they are talking about extending the green line all the way to BWI Airport. Now if Virginia do their part by selling the toll road for a billion dollars, the orange line could be extended all the way to the Dulles Airport.
It won't solve the problems of traffic congestion but extension of the metro will relieve it somewhat.