Route 66 was certified in 1926 when the nation adopted a numbered system of cross-country, interstate roads. Fully paved by 1936, Route 66 became an important and legendary highway immortalized by literature, music and television. Gradually replaced by huge interstates, Route 66 was decertified in 1985, ceasing to 'officially' exist. Well over 80% of the highway is paved, and driveable, so travel back in time, and leave your stress behind. 'Get Your Kicks on Old Route 66'.