First Colorado instituted a 419.99 mile marker on I-70 back in January. Now Idaho is following suit with its own 419.9 marker on U.S. Route 95, just south of Coeur d'Alene.
"Having a sign removed from the highway is pretty rare," says Idaho Transportation Authority official Adam Rush.
The signs are often ripped off by stoners who worship all things 420, a popular slang term for marijuana.