When tractor-trailers travel at highway speeds, more than half of their fuel is consumed simply pushing through air resistance. This resistance, known as aerodynamic drag, is a major factor affecting fuel efficiency.
In fact, aerodynamic drag accounts for roughly 65% of the energy used by a tractor when pulling a trailer. It forms at multiple points across the truck and trailer, including the front of the truck, the gap between the tractor and trailer, the sides and underbody of the trailer, and the rear. The smoother the airflow around these areas, the lower the drag – and the better the fuel efficiency.
Reducing aerodynamic drag can deliver significant fuel cost savings. Industry reports show that deploying multiple drag-reducing devices can cut fuel consumption by more than 12%, translating to an industry-wide savings of approximately $10 billion in diesel fuel costs. That’s why more fleets are adopting trailer aerodynamic products to minimize drag and maximize fuel efficiency.
Addressing Drag Across the Entire Tractor-Trailer
Over the years, trucking companies have adopted a variety of products designed to improve aerodynamics. These aerodynamic enhancements play a crucial role in reducing drag and improving fuel efficiency, especially at higher speeds where drag is at its greatest.
Each of these products is specifically engineered to target different areas of aerodynamic resistance on a truck and trailer, helping to minimize drag at multiple points.
Front-End Design Improvements
The front of a tractor produces a significant amount of drag, prompting manufacturers to explore more aerodynamic designs. Innovations such as sloped windshields and pedestal door mirrors are among the changes aimed at improving airflow and reducing resistance at the front of the vehicle.
Side and Underbody Drag Reduction
The sides and underbody of a semi-trailer contribute to roughly a quarter of overall drag while moving at highway speeds. Several aerodynamic solutions help mitigate this:
- Trailer fairings (side skirts): These panels extend along the trailer’s lower sides, preventing wind from flowing underneath and into the bogie. They are most effective when they cover from the landing gear to the front of the trailer axles, positioned close to the ground. By reducing airflow beneath the trailer, fairings can deliver fuel savings of more than 4%, according to manufacturers.
- Wheel covers and mud flaps: Wheel covers streamline airflow around the tires, while mud flaps, installed behind the wheels, can help deflect air away from the undercarriage.
Reducing Drag at the Back of the Trailer
The rear of a trailer creates another major point of drag, as air gets trapped around the tail. One solution that has historically improved efficiency is the trailer tail; a device mounted at the back of the trailer to guide airflow smoothly off the vehicle. While trailer tails have been shown to improve fuel efficiency by up to 6%, production of the product ceased in 2020.
Closing the Tractor-Trailer Gap
One of the biggest contributors to aerodynamic drag – responsible for up to 25% of total wind resistance – is the gap between the tractor and the trailer. Studies show that a gap of 18 inches or more significantly increases air resistance, while covering the gap can reduce drag by as much as 9%.
TruckWings® Technology: A Game-Changer in Aerodynamic Efficiency
Designed to combat drag in the tractor-trailer gap, the TruckWings system is a fully automated, tractor-mounted aerodynamic device that requires no driver interaction.
How It Works
- The device automatically deploys its aerodynamic panels at speeds above 52 mph, closing the tractor-trailer gap at the top and sides without distracting the driver.
- It automatically retracts when speeds drop below 50 mph, ensuring unimpeded maneuverability on city streets and tight turns.
Benefits of TruckWings Technology
- Improves vehicle stability
- Increases fuel efficiency
- Reduces aerodynamic drag
- Delivers fuel savings of 4-6%
- Achieves ROI in 18-24 months with zero operational downtime
- Operates in two positions without driver interaction:
- Panels open at highway speeds
- Panels closed for low-speed maneuvering
- Uses smart sensors to track fuel and carbon savings
- Provides uptime reporting for fleet monitoring
CASE STUDY: Learn how Ryder Systems saved 4.1% on fuel with TruckWings Technology
Maximizing Efficiency with a Focus on Aerodynamics
When selecting aerodynamic devices, fleet owners should consider products that complement one another. For instance, combining a TruckWings system with trailer fairings can further enhance drag reduction. The best solutions will depend on the specific needs of each operation, making it essential to evaluate available options carefully.
Want to improve fuel efficiency across your fleet? Contact us to learn more about how TruckWings active aerodynamics can help reduce fuel costs and optimize performance.
