(last updated 10/3/2023)
If you are familiar with the mileage signs posted at the terminus points of US 6 and US 20, you might point to those and say, "The answer is plain to see: US 20 is 160 miles longer than US 6."
If both of those signs were accurate, then obviously US 20 would be longer. But the fact is, only the US 6 sign is accurate, whereas the US 20 sign significantly overstates the true mileage. In reality, the mileages of the two routes are very close, and in fact there is every reason to believe US 6 is actually a slightly longer route.