It would not only make a good use out of the I-97 number, but also provide an alternative to the Capital Beltway that is already congested.
The southeast side of the Beltway is not all that congested. Not even close to the congestion level of the north and west sides, which an I-97 route would *NOT* help.
IMO, that part of the Capital Beltway is "on the edge" of getting much
worse, probably due to population growth in places in Calvert, Charles and Anne Arundel Counties (and in Northern Virginia). Population in Prince George's County has not changed much in recent years.
I always thought anyhow that a new I-95 alignment with a bridge south of Mount Vernon should have been built instead of the Woodrow Wilson Bridge replacement, as most of that crossing's traffic is through I-95 traffic.
Ummmmm...no. The vast majority of Woodrow Wilson Bridge traffic is DC-area traffic or traffic that has an origin or destination within DC. At best, there is about 30,000 vpd of "through traffic" on I-95. Per VDOT traffic figures, Wilson Bridge daily traffic is 150,000. That's 20%, not even close to "most".
Within the D.C. metropolitan area
Though I have seen how (mismanaged) incidents on the Southeast/Southwest Freeway in D.C. during the morning peak commute period have backed-up all the way down I-295 and onto the Wilson Bridge (before and after the Wilson Bridge widening project was completed).
2011 AADT for the Wilson Bridge (according to the Maryland Highway Location Reference) was 197,460.
Furthermore, where would you put such a bridge? Even in the 1970s when I-95 was cancelled through DC and rerouted onto the Beltway, development was to the point where you couldn't put a bridge anywhere north of Mason Neck (and if you thought the "Bi-County Parkway" folks were screaming about that road right now, Mason Neck residents would go on a murdering rampage if you were to even think of putting a bridge on Mason Neck). We're to the point now where there's no way you could put a bridge upriver of about Stafford. Best bet is just to replace the Nice Bridge and work on incremental improvements to US 301. As nice as a freeway route along 301 would be, I just don't see it happening anytime soon.
I recall one proposed crossing was near MCB Quantico and Triangle, Virginia (in other words, north of the Town of Quantico) and Chicamuxen, Charles County, Maryland (south of the U.S. Navy reservation at Indian Head).
There is a massive 500 kVa electric transmission line that crosses the Potomac near here (it crosses the river at an angle such that the Virginia end of the crossing (near Dominion Virginia Power's Possum Point electric generating station) is further north than the landing on the Maryland side). The pylons holding the line up are clearly visible on Google Maps (here