Commissioned in 1926 and dubbed the "Mother Road," Route 66 linked Chicago and Los Angeles and led thousands of people west in search of new lives. In 1926, less than half of the route was paved, and none of that paving was in the California desert, but by 1938 the entire route was paved, making it the first all-paved highway in the country. Travel between Chicago and Los Angeles then took about 5 days. During the 1930s, Route 66 served as a major thoroughfare for Dust Bowl migrants from the South and Midwest seeking better lives in California, and the traffic it carried during the Great Depression helped keep many small highway towns alive. Many towns along the route had begun as railroad water stops and grew to serve travelers with schools, depots, cafes, motor courts, gas stations, and campgrounds, though few of those services remain today. After World War II, Route 66 became a popular vacation route, and in 1946 Bobby Troup's song "Get Your Kicks on Route 66" broadened its fame. As traffic, accidents, and deterioration increased, the need for a modern transportation network became clear. In 1972, Interstate 40 officially bypassed the desert portion of Route 66, and the old two-lane road was decommissioned and turned over to San Bernardino County. In 1984, the last segment of Route 66, near Williams, Arizona, was bypassed by Interstate 40.