Method for Reducing Aerodynamic Drag on Tractor-Trailers

A bio-inspired sidewall design to increase fuel efficiency and lower greenhouse gas emissions.

The Need

Tractor-trailers are essential to the United States (U.S.) economy. The annual value of freight transported in the U.S. in 2013 was $18 trillion. Of the $18 trillion1, $11 trillion (64%) was transported by the trucking industry. Tractor-trailers consumed 109 billion liters (29 billion gallons) of fuel, which is 17% of the total U.S. highway fuel consumption. The high fuel consumption by tractor-trailers can be largely attributed to their poor fuel economy (5.8 miles per gallon), which yields higher fuel costs and significant greenhouse gas emissions. Outside of engine losses, aerodynamic losses account for the largest fraction of fuel consumption for tractor-trailers. Several aerodynamic modifications to the body of the truck and the semi-trailer have yielded promising fuel efficiency results of anywhere from 5% to 10% efficiency increase. Current efforts to improve aerodynamic performance of tractor-trailers focus on optimizing tractor design and implementing drag-reducing trailer add-on structures such as skirts and fairings. However, there is currently no practical implementations of improved trailer sidewall design.

The Technology

Researchers at The Ohio State University, led Dr. Shaurya Prakash, have developed a series of novel planar wall body designs for semi-trailers. The invention has three explicitly evaluated bio-inspired variations over the existing state-of-the-art configuration, which was used as a baseline comparison. The special geometry of the invention is effective in reducing aerodynamic drag by altering the airflow around the tractor-trailer such that the pressure incident upon the rear of the semi-trailer is increased.

Commercial Applications

  • Automotive and Trailer Design and Manufacturing
  • Aircraft and Marine Vehicle Design and Manufacturing


  • Reduced fuel costs and less frequent refueling for the operator of the tractor-trailer
  • Drag coefficient reduced by 12.9% in wind tunnel experiments, translating to 780 million gallons of fuel saved annually in the United States

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