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Bigger trailers for greater efficiency

Dick Giromini, President and Chief Executive of Wabash National, tells David Isaiah about the role of trailer design in improving truck efficiency

Freight transportation demand in the US is expected to exceed 25 billion tonnes in 2040, a figure which considers all modes of freight transportation, including road, rail, waterways and air. Of the different modes of transportation, trucking is expected to see particular growth, largely at the expense of rail and water.

In the US alone, freight transportation by road produces in excess of 1.6 billion tonnes of carbon dioxide emitted annually. This, then, translates into around 6% of total worldwide greenhouse gas emissions. Given these figures, emissions reductions in this segment will play a significant role in combatting global warming, while boosting profits for the fleets involved.

According to a study conducted by the North American Council for Freight Efficiency (NACFE), a US non-profit organisation working to double the freight efficiency of North American goods movement, fuel costs faced by the tractor-trailer industry have been swiftly and steadily increasing over the past decade, rising to US$0.64 per mile. As a result, fleets have been driven to include freight efficiency in their strategies.

Consider this: fuel usually accounts for a large, and often the largest, operating cost for fleets, even more than the costs incurred by a fleet for the driver. Despite this, there is, in general, a limited adoption of fuel saving technologies, both in North America and in Europe. Some of the factors that lead to a slow adoption of such technologies include the cost of fuel itself, the cost of technology, and capital restrictions at fleets.

According to Erik Jonnaert, Secretary General of the European Automobile Manufacturers’ Association (ACEA), the diversity of the commercial vehicle fleet affects the discussions about how to improve vehicle efficiency and safety. The incentives for improving fuel efficiency, for example, are far clearer than in the case of the passenger car market. Commercial vehicle operators spend around a third of their vehicle operating cost on fuel alone, so even slight savings can have vast impacts on the bottom line.

Asked about NACFE’s target of doubling freight efficiency in North America, Dick Giromini, Wabash National President and Chief Executive, said he believes it to be an aggressive, but achievable goal, requiring a collaborative effort between truck and trailer manufacturers. He believes that with a combination of fuel saving technologies and improved aerodynamics, up to 10% fuel economy improvements can be derived from truck trailers.

“However, fuel consumption is only one part of the freight efficiency equation. There are opportunities throughout the supply chain. We’re already seeing an increase in freight density as electronics and other products have become smaller, along with efforts to optimise packaging. Consumer goods companies are eliminating excess air space in the design of their packaging, which increases density and the effective volume of freight per load,” Giromini told Megatrends.

Europe’s freight movers have also been making strides in improving freight efficiency. In 2008, ACEA’s commercial vehicle manufacturers committed to an agenda called ‘Vision 20-20’ which aims to reduce the fuel consumption of commercial vehicles by 20% by the year 2020 compared to 2005. This is equivalent to an annual 1.3% improvement in fuel economy with commensurate reductions in carbon dioxide emissions.

Clearly, fleets are continually evaluating their operations in order to find more ways to improve efficiency – be it lane or route optimisation, reduction in empty miles, freight loading/unloading, speed limiters and other measures. According to Giromini, efficiency is being driven by new technology and design innovation. As a result, many fleets are testing and deploying the latest fuel efficiency technologies, on both tractor and trailer.

According to the NACFE study, there are around 1.5 million tractor trailers operating in the US. Together, these account for the consumption of around 26 billion gallons of diesel. To put things into perspective, every 1% reduction in fuel use translates into 260 million gallons of diesel saved, which, annually, would be worth around US$1bn.

Trailers play a significant role in improving freight efficiency, especially as it relates to fuel economy. The more aerodynamic the trailer design, the greater the reduction in fuel consumption. However, fuel efficiency through aerodynamics cannot come at the cost of cargo capacity.

Just how great are the fuel savings that technology-intensive trailers can deliver? If a fleet uses low rolling resistance tyres, combined with features to improve a trailer’s aerodynamic efficiency, such as side skirts and a tail device, fuel savings in the range of 8-10% can be gained, according to Wabash National. This is of course at highway speeds, and depends on the type of trailer used, the length of haul and freight operation.

“Trailers are regulated by overall length, width and height. Given these boundary parameters, we’ve essentially taken cube capacity to its limits with current technology. However, opportunities remain to take even more weight out of the trailer, thereby increasing effective cargo mass capacity so more freight can be hauled,” said Giromini.

There are three main ways to improve a trailer’s efficiency: reduce aerodynamic drag, improve rolling resistance and reduce the weight of the trailer. With regard to aerodynamics, the three main areas where drag occurs are the tractor-trailer gap, the side and underbody of the trailer, and the rear end of the trailer. According to a white paper on trailer technologies by the International Council on Clean Transportation (ICCT), efficiency can also be improved through the use of alternative materials such as composites and aluminium, in wheels and structural supports.

Wabash National, too, has been working to advance the science of trailer design, aimed at more effective, efficient and safer operation. The company’s current direction of development includes weight optimisation through advanced materials and the development of new aerodynamic devices and designs.

Regulations play a significant role in improving freight efficiency as well, be it tractor or trailer. In mid-2014, after the EU’s Transport Council agreed on the revised directive on the weights and dimensions of trucks, ACEA’s Jonnaert said that this provided an opportunity to reduce CO2 emissions more efficiently from heavy-duty vehicles.

“Industry should have the flexibility to make use of revised rules to deliver even cleaner and more efficient trucks in the most cost-effective manner. Allowing an extension of the current maximum length of vehicles and vehicle combinations, while complying with legal requirements, will enable the industry to incorporate both existing and future fuel-efficiency innovations into their designs,” he said at the time.

Similarly, from the trailer standpoint, Giromini feels that to make even more significant improvements in freight efficiency, one would have to evaluate existing equipment regulations, such as trailer length and weight restrictions. For example, fleets in the US are currently pushing for the approval of 33-feet double trailers instead of the existing 28-feet dimension.

If passed, less-than-truckload carriers would see an increase in their freight capacity by 18% per trailer without putting additional trucks on the highways, according to Giromini, who summed up the discussion with compelling argument: “This would not require changing any weight limits, nor infrastructure, but would have a significant effect on capacity. Said another way, at current demand levels a fleet could eliminate one tractor for every ten 33-foot combos in service. This would not only decrease fuel consumption and related greenhouse gas emissions, it would reduce road congestion and potentially enhance highway safety.”

David Isaiah

This article appeared in the Q1 2015 issue of Automotive Megatrends Magazine. Follow this link to download the full issue.