Roads around DC are a godawful mess and Google can't really be blamed for not getting everything right the first time, but it would be nice if they could fix some bugs.
First of all, in Arlington, there are streets named "n STREET N" and "n STREET S" that are nowhere near each other. This is similar to the DC system, where each street exists up to 4 times: "x STREET NE", "x STREET NW", "x STREET SE" and "x STREET SW". But, unlike in DC, there is a local tendency to write "3333 N 3RD ST" instead of "3333 3rd ST N". Google Maps standardizes these addresses correctly... some of the time. In particular, try to search Google Maps for "1521 n 12th st arlington va" and you'll get it standardized to "1521 12 st s"! This messes up things like padmapper.com, which take address data from places like craigslist where it is often listed in the informal form with the direction before the street name.
Then try this query: "22030 to dc". Why does it not take the interstate? Because some of it is HOV-only some times of day.
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Next up: some metro stations are presumed to be on freeways. Try "caron dr falls church va to west falls church station".
