4. Mon-Fayette Expressway, USA – $5.4 billion
The Mon-Fayette Expressway connects Interstate 68 with Interstate 376. It got its name combining the Monongahela River and Fayette County. The key purpose of the motorway is to connect coke- and steel-producing towns in this valley, making it vital for the local economy. This road is an alternative to Interstate 79 to the west and a significant part of our list of 10 Most Expensive Highways in the World.
