Fuel Efficiency of Semi-Trucks: Understanding Diesel Consumption

Understanding the fuel consumption of semi-trucks is crucial for both fleet operators and potential buyers. This article delves into the specifics of how much diesel a semi-truck typically uses and the factors that influence this consumption.

Trailer vs. Tractor: Where Does the Fuel Come In?

Firstly, it is important to clarify the difference between a trailer and a tractor: A trailer, by itself, uses no fuel. It is essentially a large enclosed or open container designed to be hauled by a tractor. A trailer does not have its own engine and cannot move independently. The tractor pulling the trailer is the one that consumes diesel fuel. In cases where a trailer is refrigerated due to a cooling unit, it may use a small amount of fuel when it is parked and not connected to the tractor.

Fuel Mileage of the Tractor-Trailer Combination

The fuel efficiency of the tractor-trailer combination heavily depends on the load it carries, the terrain, and the model of the truck. A tractor pulling a semi-trailer will generally achieve around 6 to 7 miles per gallon (mpg) with a heavy load. When the trailer is empty, particularly if it is a low-profile model like a grain trailer or an empty flatbed, the fuel efficiency can improve to around 9 to 10 mpg.

Fuel Tank Capacity on Semi-Trucks

The size of the fuel tanks on semi-trucks can vary significantly. Depending on the model and the intended use, a semi-truck can carry anywhere from 200 gallons to 1000 gallons in its fuel tanks. The average semi-truck may have a fuel tank capacity ranging from 300 to 500 gallons, providing a range of fuel duration depending on the fuel efficiency.

Factors Affecting Fuel Efficiency

The fuel efficiency of a semi-truck can be influenced by several factors:

Truck Model and Size: Modern diesel trucks are designed to be as fuel-efficient as possible, with some models achieving up to 10.1 mpg for long-haul operations and 8.3 mpg for urban delivery when participating in the 'Run On Less' demonstration program. Terrain and Road Conditions: Fuel consumption varies based on the type of terrain. On a fairly flat road, a semi-truck can get around 6.5 mpg. Fuel efficiency drops to about 3.2 mpg when going uphill and improves to about 22 mpg while descending. Load Capacity: The weight of the load being transported significantly affects fuel consumption. Heavier loads will reduce fuel efficiency, requiring more diesel to power the vehicle.

Real-World Fuel Cost Estimates

A semi-truck driver can expect to spend approximately $1300 to $1800 in fuel per week, depending on the current price of diesel and the terrain they are navigating. Factors such as the weight of the load also play a significant role in determining fuel costs.

For more detailed information and to learn about the best practices in fuel efficiency, explore the 'Run On Less' initiative.