Aerodynamic Device Compliance with 23 CFR 658.16(b) (4)
U.S. Department of Transportation
1200 New Jersey Avenue, SE.
October 10 , 2008
In Reply Refer To: HOFM-1
Mr. Andrew Smith
Dear Mr. Smith:
This is in response to your letter of August 21 which requested a determination of compliance of your 'Trailer Tail' aerodynamic device with 23 CFR 658.16 'Exclusions from Length and Width Determinations.' The Federal Highway Administration (FHWA) acknowledges that ATDynamics 'Trailer Tail' was tested by an independent laboratory, KARCO Engineering, and was found to be in compliance with all elements of 23 CFR 658.16(b) (4). Therefore, in accordance with Federal regulations, the ATDynamics 'Trailer Tail' aerodynamic device should be excluded from the length measurements for commercial motor vehicles.
The full test report results from KARCO Engineering were received from ATDynamics on August 25, 2008. The 'Trailer Tail' device was evaluated for compliance with the following provisions of 23 CFR 658.16(b)(4), which exclude an aerodynamic device from the measured length of a commercial motor vehicle provided:
KARCO Engineering determined that the ATDynamics 'Trailer Tail' aerodynamic device 'Passed' all of the conditions listed in the regulation, and FHWA accepts those test results. We shared these test results with the Federal Motor Carrier Safety Administration (FMCSA) and the National Highway Traffic Safety Administration (NHTSA) for their review. NHTSA identified a conspicuity marking issue that was shared with Mr. Geoffrey Johnson, Director of Regulatory Affairs with ATDynamics, and Mr. Johnson subsequently advised us ATDynamics has taken care of the issue in the manner NHTSA recommended.
The FHWA will post this letter to their Commercial Motor Vehicle Size and Weight Web site for reference by the trucking industry. We will provide this letter to the Commercial Vehicle Safety Alliance and the American Association of State and Highway Transportation Officials for their information and use and further dissemination to their roadside enforcement officials. We will also provide this letter to the Environmental Protection Agency to inform their SmartWay Program. You may consider providing this letter to individuals using the 'Trailer Tail' product for them to provide to law enforcement officials.
If you have questions or need any further assistance regarding this matter, do not hesitate to contact Michael Onder, Team Leader, Vehicle Size and Weight Team, Michael.Onder@dot.gov, 202-366-2639 or John Nicholas of the Vehicle Size and Weight Team, John.Nicholas@dot.gov, 202-366-2317.
/s/ Anthony T. Furst
Anthony T. Furst
Luke W. Loy
Collin B. Mooney
United States Department of Transportation - Federal Highway Administration