later covered by popular musician Nat King Cole who made it into a best selling record. US 66 travelers found useful advice through a guidebook, written by author Jack D. Rittenhouse, titled aptly, A Guide Book to Highway 66. US 66 also became well known for the unusual advertisements placed along the highway by Burma-Shave, a popular shaving cream manufacturer of the time. The era between 1945 and 1956 is often considered the height of popularity of US 66 travel. The popularity of the highway led to the Columbia Broadcasting System (CBS), an American television broadcast network, to air a television show called Route 66 in 1960. The decline of Route 66 The Arizona State Highway Department had spent a total of $19 million (equivalent to $ in ) on US 66 alone between 1944 and 1954. This was largely due to the gigantic increase in traffic on US 66 through Arizona over the last decade. A Flagstaff-based newspaper once stated that US 66 carried the largest number of interstate travelers of any highway in Arizona. By 1954, more than one million cars a year were traveling down US 66 from New Mexico to California. The increased traffic had also led to a greater number of car accidents and traffic jams, the latter of which earned US 66 the unfortunate reputation of being "The World's Largest Traffic Jam". By 1956, at least one out of six deaths resulting from car accidents in Arizona took place on US 66. This helped the highway earn another negative nickname, "Bloody 66". The rough shape, narrowness and safety issues along US 66 and similar highways in Arizona contributed to public sentiment towards rebuilding and improving safety along the state's highways. In 1954, President Dwight D. Eisenhower heavily endorsed the long-standing idea of constructing a nationwide network of four-lane divided superhighways. Originally proposed back in the 1930s, this system of nationwide freeways would have entirely controlled access through the entry and exit ramps, as well as grade-separated interchanges with other highways, roads, and railroads. The new freeways would also include smoother grades coupled with more gradual curves. These massive changes in highway construction were intended to help increase traffic flow and greatly reduce car accidents occurring on the national highway network. Eisenhower pushed the United States Congress to accept the idea and appropriate funding for the new system. Congress finally approved the proposal with the