US Route 666 has been reassigned as US Route 491.  The highway hasn't become any safer, but it did make some people feel better, for what it's worth. Running from Chicago to Los Angeles, there used to be a highway nicknamed “The Main Street of America”.  This highway was better known then as U. S. Route 66, and although the highway ceased to exist in 1985, its fame still lives on as probably the best-known highway in America. Route 66 ran from east to west (well, it ran from northeast to southwest in some places, to be exact), so it was given an even number, in accordance with the way the Department of Transportation numbers highways.  (North-south U. S. routes get odd numbers.  This system also applies to U. S. Interstate highways, but not necessarily to state highways.)  Over the years, some of the old U. S. highways have been decommissioned, usually in places where they cross big, empty spaces where an interstate highway would suit the need...