There is a lot of trivia and other miscellaneous information out there relating to street signs, more than we expected when we started this whole thing. For example, did you know that there is a U.S. national standard for road signage that the various states are encouraged to adopt? It is found in the Manual on Uniform Traffic Control Devices (MUTCD) promulgated (such a nice, legal sounding word!) by the United States Department of Transportation, Federal Highway Administration.
A companion document is the Standard Highway Signs manual, which is chock full of illustrations of example signs for most highway uses. There does not appear to be anything here related to normal street intersections, however.
That portion of the MUTCD that controls the use of street intersection signs is extracted in a PDF File.** You will see tidbits such as a "guidance" that street intersection signs should have white lettering on a green background. Many cities do not follow this guideline, as you can see from the collection on these pages. Also, if you have ever tried to find someplace based only on street names, you have discovered that many cities believe that if you don't already know where your street is, you should have a wreck trying to read their poorly placed signs. Especially at night.
An article that discusses road signs as factors in car wrecks, written by some Alabama laywers, discusses how poorly placed or designed signs can actually cause wrecks. About a dozen cites to reported cases are included in Part II. So if a bad sign caused your wreck, look there for help!
** To view PDF files, you will need Adobe Acrobat Reader, which you can download and install for free, or some other viewer capable of displaying PDF format files.