Tractor/Trailer Aerodynamics

Tractor-trailers constitute a significant percentage of commercial fleet vehicles on our roads, responsible for the transportation of a myriad of goods and services across vast distances. However, their impact on the environment and economic efficiency necessitate rethinking of their design and operation. The primary focus of such redesigning has been on aerodynamics improvement to minimize air drag and thereby reduce fuel consumption and greenhouse gas (GHG) emissions.

The Role of Aerodynamics in Tractor-Trailer Efficiency

Air resistance (drag) is one of the leading causes of energy loss in tractor-trailers. Studies have shown that at highway speeds, over 65% of the total energy output of a truck's engine is expended to overcome air resistance. Therefore, improvements in aerodynamics can result in significant reductions in fuel consumption and GHG emissions.

Aerodynamic Advancements in Commercial Fleet Vehicle Technology

Several advancements have been made in improving the aerodynamics of tractor-trailers. These include the development of roof fairings, side skirts, boat tails, gap fairings, and underbody devices.

  • Roof Fairings: These devices reduce air resistance by smoothing the airflow over the top of the tractor-trailer. They can result in up to 2-4% improvement in fuel efficiency.
  • Side Skirts: Side skirts minimize the underbody wind resistance. They can lead to 4-7% improvement in fuel efficiency.
  • Boat Tails: These devices reduce the low-pressure region at the back of the trailer, reducing the drag. Boat tails can improve fuel efficiency by 2-5%.
  • Gap Fairings: These are used to smooth the airflow between the tractor and the trailer, improving fuel efficiency by up to 2%.
  • Underbody Devices: These tools are designed to optimize the airflow underneath the trailer, leading to an up to 1-2% improvement in fuel efficiency.

Sustainability Impact

By improving fuel efficiency, these aerodynamic devices significantly reduce CO2 emissions. For instance, a 6% improvement in fuel efficiency can result in an annual reduction of approximately 9 tons of CO2 emissions per vehicle. This can greatly help in achieving carbon neutrality targets set by countries and corporations alike.

Total Cost of Ownership (TCO)

While these aerodynamic devices do have an initial cost, their long-term benefits outweigh these expenses, as seen in the TCO. The TCO considers all costs associated with vehicle ownership, including purchase cost, fuel expenses, maintenance, insurance, and resale value.

By reducing fuel consumption, aerodynamic devices can significantly lower the TCO. For example, a 6% improvement in fuel efficiency can result in savings of up to $5,000 per year per vehicle in fuel costs. Additionally, with an increase in fuel prices, the payback period for these devices becomes shorter, making them more economically attractive.


The advancements in tractor-trailer aerodynamics present an effective method to improve sustainability and reduce the TCO. By using these technologies, the commercial vehicle industry can play a crucial role in mitigating climate change while improving their economic efficiency.