Where the economics of land prices have run smack into stupid zoning and land use policies.
Rockville Pike between the NIH and downtown Rockville is an ugly mess of an edge city. Like Tysons, it has too much density to be truly car friendly, but all the ugliness of suburbia: strip malls set back behind acres of surface parking.
Essentially these are the worst of both worlds kind of places, dense enough to have the unpleasant aspects of density but without the sensible land use policies which would allow the good effects of density to appear.
I’m not confident than many of them can be sensibly reshaped, but the ones which probably can be are the ones which are on a decent transit line. Access to mass transit reduces car dependency at least for some, as if someone in your household can use it to commute you can have one fewer car.
For places like Tysons, I’m not sure whether it’s transit lines to elsewhere that will make a difference. What they need is transit lines so that you can get pretty much anywhere out your front door, or from one store to another without getting in a car. Tysons has pretty much whatever kind of food, retail, service businesses and so forth you might want within no more than a mile of what high-density housing there is. But you can’t get there without navigating one or two limited-access highways, parking anywhere up to a quarter of a mile from your destination, hoofing it, and then reversing the process when you’re done.
What’s needed to make places like that livable with less car is some kind of trolley grid — start with just a series of horizontal elevators that slash the time to get to or from the boundaries of each parking lot, then expand with service along the strips and across the roads (bus, trolley, monorail, self-driving pod, zipcar, who the heck cares) and at least you won’t have the constant traffic of cars going two miles to get to places half a mile apart, and then back. Then play with some tax and zoning policies to encourage the notion that people living in all that ugly housing actually work in the vicinity instead of 30 miles away and vice versa, and you’d have the beginning of something that didn’t suck.
Oh, and all the pedestrian and mass-transit overpasses would look really cool, like a city of the future should…