The main point was the prediction vs. the actuality of the cost.
Ever think that's because the Interstates became more successful than they predicted...
and we built a much larger Interstate system than they predicted?
"During debate leading up to the Federal-Aid Highway Act of 1956, Congress used an estimate of $27 billion. This estimate was flawed in several ways. It was based on a report by the U.S. Bureau of Public Roads (BPR), which covered only the 37,700 miles designated in 1947. The BPR estimated that to build this mileage in 10 years to meet 1974 traffic needs would cost $23.2 billion, based on midyear 1954 prices. Second, President Eisenhower's Advisory Committee on a National Highway Program under General Lucius D. Clay (Rt.)—known as the "Clay Committee"—added only $4 billion for urban feeders and collectors, bringing the total to $27.2 billion. Considering that the BPR had assumed urban-rural costs for the mileage designated in 1947 would be split $12.5 billion-$10.7 billion, and that an additional 2,300 miles of urban routes had been designated in 1955, the Clay Committee's estimate was flawed.
Beyond the errors in the initial estimate, the 1956 Act added 1,000 miles to the Interstate System. The Federal-Aid Highway Act of 1968 added 1,500 miles, and subsequent legislation increased the mileage as well. In addition, design standards were stricter beginning in 1956, and compliance with essential environmental requirements enacted in the 1960s added to the cost of projects. As might be expected, inflation was a major factor as well.
Government cost figures rarely reflect the actual cost.
They are just thinking too small here.
They should make it the full 250 miles from Atlanta to Nashville.
This could become the great southern corridor like DC to Boston.