Concerning Salt Lake City, I found this:

The highest numbered street almost has to be in metro Salt Lake City,
where addresses take the form "2800 West 30800 North" (and 30800 North
is the street name). In any other place, that street would be called
308th St. if it were numbered at all. That numbering system extends
into most (all?) of SLC's suburbs, but I don't know what the highest
numbered street is, only that it's at least five digits.

It's in a discussion of high numbered streets which you may be able to find at http://newsgroups.derkeiler.com/Archive/Misc/misc.transport.road/2005-08/msg02352.html