Opinion: Fight Fuel Prices With Side Skirts

By Sean Graham

President

Freight Wing Inc.

This Opinion piece appears in the June 13 print edition of Transport Topics. Click here to subscribe today.

The average price of a gallon of diesel fuel the week of June 6 was 18% higher than it was at the beginning of this year, according to the U.S. Energy Information Administration, and the June 6 price of that fuel in California was 20% higher. Consequently, the payback of fuel-saving strategies such as trailer aerodynamics — side skirts, for example — has increased proportionally.

Although the price of diesel probably will continue to behave like a theme-park roller coaster with occasional drops between its peaks, it’s obvious that costs could go higher, particularly if events in the Middle East lead to further political instability or the value of the U.S. dollar goes down further as a result of debate over the federal debt ceiling.

In California, trailer aerodynamics technology has become a matter not of “if,” but “when.” Fleets eventually have to install trailer aerodynamics to be in compliance with the California Air Resources Board Heavy Duty (Tractor Trailer) Greenhouse Gas Regulation. The rule already applies to 2011-model dry-van trailers, and by 2013, any 53-foot trailer entering the state must have SmartWay-certified aerodynamics and fuel-efficient tires, unless fleets sign up for optional phase-in compliance plans.

If you do business in California, by installing trailer side skirts now instead of waiting for the CARB rule to come into effect, you can take advantage of savings of anywhere from 4% to 7% in fuel economy, depending on the particular skirt product and your fleet’s operating conditions. Payback can happen in fewer than 50,000 miles of trailer use. On top of that, government grants may be available to help you pay for their installation because most side skirts on the market today are SmartWay-verified and therefore eligible for grant consideration.

Achieving improved aerodynamics now means generating returns on your investment sooner, rather than later, creating a distinct competitive advantage. Sales of side skirts, which at our company have increased threefold over the past year, are certainly indicative of this trend.

What should you look for when choosing side skirts? Here are some useful tips:

• Consider any testing the side skirt manufacturer has done to prove fuel savings. Leading manufacturers invest heavily in testing by the Society of Automotive Engineers/Technology & Maintenance Council (SAE/TMC) to quantify results, while working with fleets on their own testing programs. Typically, they see as much as a 7% improvement in fuel economy during track testing at constant highway speeds. However, many variables can affect performance in real-world fleet operations. Fleets typically should expect 4% to 6% improvements, depending upon their application and the driving environment. Average speed plays a large role because aerodynamic drag increases exponentially the faster you drive.

• The best lightweight aerodynamic devices in the aftermarket weigh as little as 180 pounds and can be installed by factory-authorized shops or done in-house by operators, with no special tools required. Installation takes three to six hours, depending on the product and the technician’s experience.

• Durability and impact-resistance should be top criteria when spec’ing side skirts. The material used in their construction ranges from aluminum to fiberglass to plastic. Some are one-piece, while others comprise multiple pieces for easy maintenance and replacement.

Some manufacturers use aluminum or fiberglass composites in the construction of their trailer skirts, while others use high-grade plastic, which bends easily and wears well when the bottom edge is scraped over pavement. That’s an important point because the key to optimum aerodynamics — and fuel economy — is keeping fairings close to the ground.

• Pay attention to the mounting bracket system. Can the fairings flex? The best trailer skirts have impact-resistant mounting and support brackets to absorb and deflect blows. To achieve side-skirt life of 10 years or more, it’s important to have a mounting bracket system that can take a lot of abuse. Steep loading docks and railroad crossings might damage or break a side skirt without an adequate system.

• As the federal government’s planned requirements for minimum fuel economy and limited carbon dioxide emissions kick in later in the decade, the trucking industry will need to make even more improvements in fuel economy. Many millions of dollars already have been earmarked by the U.S. Department of Energy to accelerate the process.

Leading trailer wing manufacturers will help the trucking industry meet those minimum fuel-economy standards and emissions-reduction goals with products that can help fleets and operators realize a 15% improvement in fuel economy performance over similar trailers operated without fairings. This would come from a combination of side skirts, gap fairings (to streamline turbulence between the tractor and the trailer) and fairings at the end of the trailer.

Manufacturers are well on course to make this happen, and initial testing is encouraging. But in the here and now, side skirts already are available to streamline not only the trailer but your fuel bill as well. With return on investment that can be measured in months, not years, trailer skirts are quickly becoming a common sight on the interstates.

Freight Wing Inc., Seattle, makes and distributes trailer side skirts, belly fairings, gap fairings and customized products for a variety of trucking applications.