How much CO2 do semi-trucks emit?

Semi-trucks are responsible for a large portion of transportation-related carbon dioxide (CO2) emissions. On average, a Class 8 semi-truck can emit about 1 to 1.4 kilograms of CO2 for every gallon of diesel fuel consumed. Depending on the truck's engine efficiency and driving conditions, this equates to approximately 25 pounds of CO2 emitted per mile traveled. A fully loaded semi-truck traveling long distances can release around 200 to 400 pounds of CO2 per hour while idle or in slow-moving traffic. These trucks may accumulate up to tens of thousands of miles annually, thus contributing considerable amounts of greenhouse gas emissions over their operational lifetimes.