If you remove the I-395, I-695, I-66, I-295/DC-295 and US-50 freeways from inside the Capitol Beltway it would seem like the end of the world to commuters all over the Greater DC area. That especially goes for I-395.
None of those freeways really cut through the heart of the city. They take you to the edge of the CBD but you have to go the rest of your way on local roads. The closest you can argue is the Center Leg Freeway portion of 395 which ends at NY Avenue, but most commuters don't go that far north on 395 anyway.
While none of those freeways serve the D.C. CBD per se, what they do particularly well is distribute traffic destined for in & around the National Mall, particularly tourist traffic, which makes up quite a bit of the overall vehicle volume in the city. And despite the occasional rumblings about tunneling an I-66 extension under K Street (which don't go anywhere and are just talk), the prospect of system expansion functionally died about 45 years ago. On the other hand -- except for the Whitehurst -- any clamoring for teardowns doesn't seem to have gained steam either; for the most part, the status quo seems to be working at least satisfactorily.
Maybe like on the 4th of July, but are you serious?
Besides, you just made my point. Freeways don't need to cut through the city center to be effective...they just have you get you close by and onto a sensible portion of the local grid. Many large cities in Europe (e.g. Paris, Moscow) have multiple train stations around the core of the city since they couldn't run tracks through the middle of the city...same concept.
Most of the times I've been to D.C. (and never on 7/4!) for research interviews and archival research, I've encountered large numbers of tourists (it's always fun to converse with them to ascertain their feelings about being in "ground zero" of institutional power & prerogative). The times I've asked, more are getting around the area by car (often short-term rentals) that availing themselves of transit (if they knew/understood the network better, that figure may decrease -- but "short-termers" usually don't bother to scope out transit unless they're doing a carless visit.
And in the case of D.C., through-put freeways wouldn't be much help in getting around the city; that point is correct --
in that particular instance!] The traffic patterns that exist with the truncated network that there is in D.C. are long settled; the fact that while agencies and institutions are spread around the city; it's compact enough (by design!) so that transit and walking are a viable option; the distance between any two points is only a few miles. And D.C., for the most part, emanates radially from a series of hubs at or flanking the mall area.
But that doesn't indicate that the model that works for D.C. is in any way portable; the city configuration is completely different from a variegated environment such as posed by Dallas and most other cities. Existing freeways are, in most of these cities, part of the regional economic structure, utilized for commerce and access by residents of the region at large; the city just happens to be where much of the "action" occurs, thus it's a common destination from within and out of the greater area.
One additional thing to consider -- not all trips into and out of city centers are carefully planned and carried out; a lot of commercial and social activity occurs because one is near a particular location and realizes that there's something that "needs doing" along the way -- but only if it's moderately convenient to do so. "Slicing and dicing" freeways and thus forcing traffic onto surface streets turns that equation of convenience on its head; it becomes a bothersome "forced march" through areas previously not traversed, adding the time needed to get from point A to point B to the time allotted to conduct one's business -- where previously it was a matter of exiting the freeway, "taking care of business" and popping back onto one's way.
But what I don't understand is the "zero-sum" approach to urban freeways displayed by those with an urbanist bent -- and the I-345/Dallas scenario is a prime example of this train of thought. Solutions have been proposed to get rid of the eyesore that is the elevated freeway by sinking it below grade, with the surface being a commons-type facility geared toward providing an uninterrupted city experience. But some folks aren't satisfied to get what
they want -- they have to also see that those not subscribing to their particular viewpoint
lose something in the process. The driving public seems to be viewed as a pariah -- or worse -- by such activists, not worthy of any consideration except banishment to the perimeter. The prevailing sentiment here seems to be the age-old "if you're not with us you're against us!" credo (one which I personally find not only functionally inoperative/worthless but patently stupid). Except as an indicator of the type of argument to be avoided at all costs, this sort of partisan discourse has no place in practical policy discussions. Just because a human being lives in an outlying area -- and wants to occasionally avail one's self of urban amenities -- doesn't make them any less worthy than a city-center apartment dweller. It's called
tribalism, folks -- and is simply an unnecessary distraction from the process of arriving at policies and solutions that benefit the greater number rather than simply the most vocal and adamant!