TrailerTail manufacturer asks DOT for mounting exemption

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Updated Feb 14, 2018
Stemco’s TrailerTail aerodynamic devicesStemco’s TrailerTail aerodynamic devices

TrailerTail manufacturer Stemco is petitioning the DOT for an exemption to allow rear identification and clearance lamps to be mounted lower on van trailers and box trucks than currently permitted by federal regulations.

In an exemption request to be published in the Federal Register on Friday, June 10, Stemco asked the Federal Motor Carrier Safety Administration to allow it to move the lamps lower so the TrailerTail units can be flush with the top of the trailers to maximize their aerodynamic effect.

Rear identification lamps are defined by the National Highway Traffic Safety Administration as three red lights to indicate the presence of a wide vehicle. Rear clearance lamps are defined as a minimum of two red lights to show a vehicle’s width that may not be combined with tail lights.

The current regulations state rear identification lamps have to be mounted “as close as practicable to the top” of the trailer, with one “as close as practicable to the vertical center line and one on each side of the center lamp,” spaced between 6 and 12 inches apart. Regulations also require one clearance lamp to be on each side of the vertical center line to indicate overall width, and both must be “on the same level and as high as practicable.”

Stemco says for new trailers, the TrailerTail top panel is mounted 1.5 to 3.5 inches below the top of the trailer to comply with the current regulations, but adds the “inset creates an unaerodynamic gap as airflow transitions from the trailer roof onto the TrailerTail panels and has prevented TrailerTails from delivering the maximum available fuel economy benefit.”

The company adds that relocating the lights to a lower position is “equivalent to the current lamp location on a flatbed trailer or intermodal chassis,” therefore not impacting safety.

With the upcoming implementation of Phase 2 of greenhouse gas and emissions standards for medium- and heavy-duty trucks, Stemco says many carriers are looking at TrailerTails to help meet the proposed trailer standards, as well as the California Air Resources Board regulations for van trailers that has been in effect since 2010. This week, the final version of the second round of emissions and fuel efficiency regulations advanced to the White House for clearance before it’s published, likely later this year.

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Stemco adds that without the exemption, “it will be unable to verify fleet performance of a higher performance TrailerTail design that is expected to provide the maximum available fuel economy benefit that may be necessary in order to meet future fuel efficiency requirements.”

FMCSA is asking for public comment on the exemption request, which have to be submitted within 30 days of the document’s publication in the Federal Register on June 10. Comments can be made by searching Docket No. FMCSA-2016-0167 at starting June 10.

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