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Don't extrapolate too far from a small sample. I don't think anyone would recognize you as a non-Californian just for saying "there are".
Now, if you refer to highways US-101 or I-5 as anything other than "The 101" or "The 5", then you're clearly not from here!
Wikipedia does not back me up on this, however. Apparently the "The" names are SoCal-indicative. This has not been my experience here in NorCal.
FWIW, I learned the meaning of "based" once, but I found the explanation dissatisfying and promptly forgot it. :)