Without a doubt, the simplest thing you could do to improve my new neighborhood would be for the city to take Cary Silverman’s suggestion and scrap the giant green highway-style signs on New York Avenue east of Mount Vernon Square. It’s a wide street, yes, but it’s just not a highway and shouldn’t have the aesthetic attributes of one.
More generally, I think it’s important for cities to send the write subconscious cues to drivers. Of course any city of any size is going to have private motor vehicles zipping hither and yon, to say nothing of delivery trucks, taxis, buses, and emergency services. But precisely because a successful urban area will inevitably be heavily trafficked, it’s important for the design elements to send the message that the city is a place where people will be walking around and that drivers’ job is to accommodate themselves to that reality. If you send the signal that the streets belong to the cars and it’s the people who are the interlopers the cars will drive the people out.