Hi Adam! I know there is such a site/map....I just don't know what it is. But this might be it:
If you live in the Phoenix metro area you can use the Maricopa County bicycle map to find a safe route to work MAG Bicycle Route Map Front MAG Bicycle Route Map Back (request a free hard copy by calling 602-254-6300):
If you live in Mesa, you can also get a Mesa city bicycle map (call 480-644-2160 to request a hard copy).