Ryan Avent argues that increasing building heights in Washington DC and Northern Virginia are not a simple picture;

So let's think about the effects of doubling density in Fairfax and the District. Now on the one hand, the benefits to doubling density in Fairfax are likely to be larger than those in Washington for reasons of scale alone -- in the Fairfax example, more people are added. That makes for a deeper labour pool, a larger skills base, and so on.

On the other hand, Fairfax density is likely to be less effective density. Fairfax is built in a fairly standard, suburban way. It's not built at a walkable scale, the road system is arterial rather than gridded, transit options are limited, and so on. Doubling density, absent major infrastructure improvements, might actually reduce the metropolitan access of Fairfax residents

This would match my experiences of living in Northern Virginia. It is very much a feeder system of arterial networks that guide the car to Washington DC or the inner urban suburbs of Alexandria and Arlington.