US 66 underwent many improvements and realignments over its lifetime, but was officially removed from the United States Highway System in 1985 after it had been replaced in its entirety by segments of the Interstate Highway System. Portions of the road that passed through Illinois, Missouri, New Mexico, and Arizona have been communally designated a National Scenic Byway by the name "Historic Route 66", returning the name to some maps. Several states have adopted significant bypassed sections of the former US 66 into their state road networks as State Route 66. The corridor is also being redeveloped into U.S. Bicycle Route 66, a part of the United States Bicycle Route System that was developed in the 2010s.