"Sic" means "that's not a mistake". When quoting, it often means "I didn't make the mistake, I faithfully copied somebody else's" but when writing your own stuff, it means "I didn't make a mistake; I meant to write that".
Ok, gotcha. I'm familiar with it (in the "sic erat scriptum" sense) for other people's writing but I've never seen it used in an original writing like that.
Not sure I get it here either, since most cities I can think of have multiple highways going through them, but thanks for the clarification. Always glad to expand my understanding of language.