Understanding Fuel Consumption in Semi Trucks and Trailers

The question of how much diesel a semi takes can be complex, as it depends on whether you're asking about the truck itself or the semi-trailer it hauls. Here, we break down fuel consumption for both, focusing on the environmental and economical aspects that impact trucking operations.

Trailer Fuel Usage

No Fuel Consumption without a Truck: A semi-trailer by itself, like any trailer, does not have an engine or an internal combustion system. Therefore, it does not consume any diesel fuel. It is purely a carriage designed to transport goods. The fuel usage comes into play only when a tractor (the pulling vehicle) is hooked up to the trailer.

When a tractor is connected, the truck's fuel consumption depends on several factors, including the load, terrain, and trailer design. Tractors pulling grain or flatbed trailers can achieve mileage around 9 to 10 miles per gallon (mpg) when empty, due to their low profile design. With a heavy load, the average consumption is about 6 to 7 mpg.

Truck Fuel Efficiency

Interstate Driving: On highways, the average semi truck achieves around 6.4 miles per gallon. Short-haul urban delivery, however, is more challenging, with an average of 6.0 miles per gallon. This is due to the urban topography that includes more stops and slower speeds.

Best Practices: Research by the National Alternative Fuels Charter Energy Alliance (NACFE) and Rocky Mountain Institute (RMI) in "Run on Less" demonstrates that some of the most efficient long-haul trucks can achieve up to 10.1 miles per gallon, while smaller, urban delivery trucks can reach up to 8.3 miles per gallon. These standards are crucial for both reducing emissions and cutting operational costs.

Carrying Capacity and Fuel Tanks

Truck Fuel Efficiency: Variables: The diesel engines in semi-trucks can vary in size and capacity, with some models holding up to 1000 gallons of diesel. Commonly, though, tanks range from 200 to 300 gallons. The actual consumption depends on the truck's size, driving conditions, and the type of haul.

Real-World Cost: The cost of fuel per week can vary widely. A seasoned driver might expect to spend anywhere from $1300 to $1800, depending on fuel prices, terrain, and load weight. Factors such as high-speed highways and steep inclines can significantly impact fuel consumption and, consequently, costs.

Conclusion

Understanding the nuances of diesel consumption in semi-trucks and trailers is essential for both commercial operations and environmental considerations. Whether you're a seasoned truck driver, a freight company manager, or an interested bystander, this information can help you make informed decisions that impact both your business and the planet.

[](Run On Less: Presented by NACFE and RMI)