I had the opportunity to meet with state Emergency Management officals about a year ago. They did learn something from the mass exodus caused by hurricane Floyd. While the North bound lanes of the expressway were a huge parking lot, the south bound lanes were completely empty.

Since then the state has made preparations to convert the interstates that pass throught the state of North Carolina, to all one direction. They flew a plane over all the the interstates and took arial pictures of each intersection. From that they deterined how many cones, orange barrels, and law enforcement it would take to redirect each intersection.

There are a number of issues with haveing traffic flow the wrong way on an interstate. All the signs are backwards. How to drivers know where is a good place to exit for food, fuel, restrooms, lodging, etc? All the stoplights and signals to regulate flow onto or off of the interstate are backwards. So you must have law enforcement at every single intersection to direct traffic. You must have cones, barrels or other devices to help redirect traffic around all the considerable normal markings.

Once in place and flowing is probably the easiest part of the job. But the conversion from 2 way to one or back will be significant. You would have to shutdown all entrances into the southbound for some period of time to clear it of any traffic. Then open it up to only North bound. Later it would have to be shutdown again, cleared of any wrong way traffic and then reopened for normal traffic.

Think about how an accident backs up traffic during normal situations. Imagine an accident on the south bound that is now traveling north. Emergency services may be stationed North of an accident and need to travel south to get to the scene. So they must travel surface strees to get South of the accident, enter the expressway system and then travel north to the scene. But which side of the expressway? If they are barriers or guard rails and the accident is in the "north bound" lane but all traffic is flowing North, which side does the caller really mean?