There are plenty of lots capable of accessory dwelling units in Upper Northwest
Alley-Palooza of its own. This poster and event is from Seattle.
Much of the most vociferous opposition to the potential for "alley dwellings" on the rear of housing lots in Washington, DC--something that is legal now in certain residential zones, has been grandfathered in for some dwellings/carriage houses that wouldn't be legal now, but for existing buildings, but mostly isn't legal in DC--comes from Wards 3 and 4 in Upper Northwest.
Yet many of the lots are appropriately sized for such dwellings.
And the likelihood of residents--the proposed changes to the zoning code would only allow accessory dwelling units on owner-occupied lots--renting units to "bad tenants" is extremely unlikely.
See "Will carriage houses destroy city life as we know it?" and discussion on the topic from Greater Greater Washington:
-- Walkability and garage apartments are not just for the young
-- Panic! Your alley could have a cute, clean little brick house!
-- Why the angst over accessory dwellings?
We went to an estate sale on the 4400 block of River Road NW over the weekend, and the block was full of lots with garages, at least one might have been semi-converted into something more, demonstrating the potential of accessory dwelling units here.
The block is 0.46 miles from the Tenleytown Metro Station and 0.59 miles from the Friendship Heights Metro Station.
Personally, I think that ADUs should be prioritized, when they can be easily accommodated, in transit station catchment areas, up to about one mile from the station--easy walking distance is up to a half-mile, and biking distance is up to one mile.
Note the extension on this building. The plantings obscure the building somewhat. But if you zoom in, you can see it better.