Tierra del Fuego - End of the Pan American Highway

This sign says that Alaska is 17,848 kilometers away (or about 11,000 miles). However, I've read other reports that the Pan American Highway is from 16,000 - 29,000 miles if you start at Deadhorse in Alaska and wind through the entire network of roads. I guess the only way to get the real mileage is to drive it yourself! However, when you reach the Darien jungle of Panama, abotu 60 miles of the trail is inaccessible to motor vehicles. You'll have to take a boat around this section of the undeveloped road if you decide to drive the length of the Americas!