It talks about a 'solstice' alignment and 'east-west' streets (which would imply equinotial solar alignment, not solstitial).

Actually the streets aren't oriented due E-W in any case.

Washington's more interesting in my view, because there are a number of alignments that are designed to be astronically-based. They're there as part of the masonic heritage of that city.

One of the most obvious is the equinox alignment for the Washington Monument and Lincoln Memorial, but there are others related to the constellation Virgo.
--
simon