About a year ago I remember looking at a map of Allegheny County that showed the legislative state routes and the names of county roads. It was on a site with a viewer app that you can zoom in with (I don't think it was Zoomify but something custom). Anyone know what I'm talking about?
Never mind - found it.
http://images.library.pitt.edu/cgi-bin/i/image/image-idx?view=entry;cc=darlmaps;entryid=x-darmap0830
http://images.library.pitt.edu/cgi-bin/i/image/image-idx?view=entry;cc=darlmaps;entryid=x-darmap0831
You may also find this useful:
http://www.dot.state.pa.us/internet/bureaus/pdplanres.nsf/infoBPRHistoricCountyMaps