@levisan the writer chooses their dialect of English. If they randomly jump between color and colour in the same project, take points off for being sloppy or copying and pasting random text from everywhere.
Also, never say "2 miles, or 3.2 kilometers…" If the reader can't picture miles or kilometers in their head, I don't care where they're from; that's illiterate and it's not the writer's problem. Pick one measurement system and use it.
@levisan I would mix dialects just like that -- not rewriting quotes to conform to my language standards, unless the original has an unclear meaning.