What is typical fuel mileage for newer diesel semi tractor-trailer rigs on the highway?
The typical fuel mileage for newer diesel semi tractor-trailer rigs on the highway varies depending on several factors, including the specific make and model of the truck, the weight of the load being carried, and the driving conditions. Generally, though, most modern semi trucks achieve between 6 and 8 miles per gallon when cruising at highway speeds. Some newer, more aerodynamically efficient models can even approach 10 miles per gallon.