In the past couple of decades, Kentucky has built bypasses of cities across the state. It is standard to practice to designate the new bypass route using the existing route number and to redesiginate the original route as a business route. For instance, when a Glasgow’s western bypass was constructed it was designated US 31E and the existing route was redesiginated Business US 31E. Other examples are US 231 in Bowling Green and US 68 in Auburn.
In official route logs, business routes are identified by the suffix X. So Glasgow’s Business 31E appears as US 31EX in official route logs. Usually these route number suffixes are usually secret: that is they only appear in route logs not on actual signs; however, there is one exception: Mount Washington’s US 31EX.
In the summer of 1996, the Kentucky Transportation Cabinet opened a new four lane bypass to the east of Mount Washington. The US 31E designation was moved from streets through downtown to the new bypass, and the old route of US 31E was designated US 31EX. Instead of erecting “Business US 31E” along the route, the transportation cabinet erected “US 31EX” signs all along the route of old US 31E. As far as I am aware, this is the only place this occurs in Kentucky.
