In the last five years it’s likely you’ve seen an explosion of trailers sporting side skirts and tail fairings. In large part, the vast increase is a result of regulatory changes in the state of California. While there was some hand-flapping when it was introduced by the California Air Resources Board in 2009, it didn’t take long for motor carriers to realize that this is one regulation that would actually help save them money.
Although many at first thought the regulation unnecessary, it served in large part to help increase the focus on aerodynamics and fuel cost savings. Under the rule, 25-foot box-type trailers – whether dry or reefer – must be equipped with SmartWay-approved side skirts or tail fairings. It requires a 4 to 5 percent fuel economy savings when combined with low-rolling-resistance tires.
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There Will Be Exemptions
Since the rule was implemented, however, there have been a host of exemptions that allow for varying degrees of compliance dates depending on fleet size and operational engagement (I.E. Long-haul or regional).
This presents a challenge for smaller fleets. It becomes difficult for them to figure out which exemptions apply to them and whether or not their fleet meets the requirements. As a result, some fleet owners are getting hit with citations merely for not knowing the exemption date for their fleet.
And as many of the exemptions reach their sunset period, the certainty surrounding these accessories remains. As Phase 2 of the federal greenhouse gas regulation hits the national stage following the conclusion of the comment period, using items like side skirts and tail fairings will certainly become nearly ubiquitous.
A Rule For All Trucks
If the Environmental Protection Agency’s Phase 2 rule remains largely unchanged following the end of the comment period, fleets nationwide should get prepared to start spec’ing their trailers to help aid in tractor fuel economy.
And the proposal governs more than just side skirts and fairings. It also contains language on LRR tires, automatic tire inflation systems and other lightweight components. Non-box trailers are not left out. While they may not require certain aerodynamic components, they will still need LRR tires and automatic tire inflation systems.
What To Consider
If the rule goes nationwide, expect many of the same problems faced by California drivers. If you are operating in one of these fleet types, pay extra care to how closely these compliance measures apply to you:
- Fleets with high concentrations of regional or local work.
- Parts of the country/region with lower speed limits.
- Fleets with high trailer-to-tractor ratios.
- If you are a leasing company or non-owner of a trailer.
Also keep in mind that the aerodynamic challenges of the day will be met by new technologies tomorrow. Our understanding of fuel economy and performance engineering will continue to evolve. Still, some say there is a finite number of ways that you can treat a trailer before there’s no more tht can be done.
There are limitations at play, after all. How effective a side fairing is, for example, is limited by its dimensions. Try to design taller or longer skirts and then you have to worry about ground strikes or trailer access for maintenance purposes.
As seen when the EPA unveiled their SuperTruck Project, these problems can be overcome. Even today, aero research technicians are testing out advances new designs, aided by such innovations as geometric shaping, vortex generators and longitudinal grooves.
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As new nano-materials come online, expect new advances in the way air flows around the trailer, as well. Air-flow separation and wake management are exciting new areas of research in materials science. But the question remains, how much will you see of this technology?
Well, if the government has anything to say about it, you might be seeing a lot more. And while it’s easy to dismiss government regulations as overly onerous and burdensome, in this case, it might not be such a bad thing.