From the Town of Cary's Bicycle Plan FAQ:

The NCDOT standard for a wide outside lane as a bicycle facility is 14 feet. The Town of Cary will apply this standard to all new thoroughfares. (For example, NW Cary Parkway from Evans Road to High House Road is a designated bicycle route with a 14' wide outside lane.) For existing thoroughfares, the Town will begin restriping outside lanes of multi-lane roads (at least two lanes in each direction) to create a 13-foot outside lane and an 11-foot inside line. This will create additional width for bicycles