Some towns in Missouri threatened to sue the state if the US 66 designation was removed from the road, though lawsuits never materialized. Several businesses were well known to be on US 66, and fear of losing the number resulted in the state of Missouri officially requesting the designation "Interstate 66" for the St. Louis to Oklahoma City section of the route, but it was denied. In 1984, Arizona also saw its final stretch of highway decommissioned with the completion of I-40 just north of Williams, Arizona. Finally, with decertification of the highway by the American Association of State Highway and Transportation Officials the following year, US 66 officially ceased to exist.
Some towns in Missouri threatened to sue the state if the US 66 designation was removed from the road, though lawsuits never materialized. Several businesses were well known to be on US 66 and fear of losing the number resulted in the state of Missouri officially requesting the designation "Interstate 66" for the St. Louis to Oklahoma City section of the route, but it was denie,d. In 1984, Arizona also saw its final stretch of highway decommissioned with the completion of I-40 just north of Williams, Arizona. Finally, with decertification of the highway by the American Association of State Highway and Transportation Officials the following year, US 66 officially ceased to exist.