"US78, internally designated by the Alabama DOT as State Route 4 (SR4), is a major east-west highway across the central part of the Alabama. Due to the construction of I22 along the US78 corridor west of Birmingham, part of US78 is temporarily SR5 only, since that part of the new I22/US78/SR4 is not completed. US78 roughly parallels I20 from Birmingham east to the Georgia state line. The only section of SR4 that is signed is along the completed sections of future I22 (Corridor X - Appalachian Development). As of December 2007, Corridor X is open from the Mississippi State line through the West Jefferson community, rejoining the old alignment near Graysville." ** What? No wonder the '08 version of MS Streets & Trips has a brain fart when you're driving from Birmingham to Memphis on US78. You will get a constant "off-route" message because the software/GPS cannot find the road. Just shut it off and call for directions. US78 will "reappear" as you move away from Alabama into MS closer Memphis or in the other direction east closer to Birmingham. http://en.wikipedia.org/wiki/U.S._Route_78_in_Alabama
