The story -- and it is difficult to confirm or deny -- is that Cyrus Avery, the chief champion of a designated federal route between Chicago and Los Angeles, agreed to this number because it was easy to remember and had a nice ring to it.
Since U.S. Highway 66 ceased to exist in 1985, it would be impossible to travel across it.
However, one could leave Chicago, drive on several hundreds of kilometers on roads that USED to be part of this highway, and arrive in California in a week to ten days.
Until it ceased to exist in 1985, U.S. Highway 66 went through New Mexico. One can still drive on portions of what used to be this highway in that state.
The construction of Route 66 began in November 11, 1926.