BTW, the answer is to get businesses to move out into the country. After all, in the internet age, a fair number of these jobs could be done from anywhere.
This is especially true in the DC area. There is almost no reason for a million people to be commuting into DC each day just to push papers around and answer phones and do office work.
If we spent a billion dollars moving some government work into the Maryland and Virginia suburbs, we wouldn’t have to widen the roads, or spend more on the subway and buses.