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Interpretation Letter 1(09)-1 (I) - Definition of Standard Statement

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DOT Logo Memorandum
U.S. Department
of Transportation
Federal Highway

Subject: INFORMATION: FHWA Official
— Manual on Uniform Traffic
Control Devices
Date: October 1, 2010
From: Jeffrey A. Lindley
Associate Administrator for Operations
In Reply Refer To: HOTO-1
To: Chief Counsel
Directors of Field Services
Federal Lands Highway Division Engineers
Director of Technical Services
Division Administrators
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The Federal Highway Administration (FHWA) is issuing this official interpretation in response to numerous letters of concern received from AASHTO, as well as a number of State departments of transportation, regarding the addition of a sentence to the definition of Standard in Section 1A.13 and the removal of certain Guidance information in Section 1A.09 of the Manual on Uniform Traffic Control Devices (MUTCD).

As a part of the 2009 MUTCD Final Rule, a statement, "Standard statements shall not be modified or compromised based on engineering judgment or engineering study" was added in the Section 1A.13 to the definition of Standards and the following text was deleted from the Section 1A.09:

"The decision to use a particular device at a particular location should be made on the basis of either an engineering study or the application of engineering judgment. Thus, while this Manual provides Standards, Guidance, and Options for design and application of traffic control devices, this Manual should not be considered a substitute for engineering judgment. Engineering judgment should be exercised in the selection and application of traffic control devices…"

The AASHTO Board of Directors and the National Committee on Uniform Traffic Control Devices (NCUTCD) passed resolutions on this matter. These resolutions and letters requested that the changes in the 2009 MUTCD language described above the reverted back to the 2003 MUTCD language.

Because the MUTCD is approved and incorporated by reference in a Federal regulation, it can only be revised through the formal Federal rulemaking process. However, we believe that AASHTO's and NCUTCD's concerns may be addressed through the issuance of an official interpretation of the 2009 MUTCD that clarifies the meaning of the subject language until such time as revised language is proposed and adopted through the rulemaking process.

The MUTCD recognizes that the use of engineering judgment and studies is a fundamental tenet of the application of traffic control devices. It is for this reason that, in most cases, the selection of a particular device is not required by a Standard but is determined by engineering study or judgment. Additionally, many Standards in the MUTCD specifically require, by explicit language in the individual Standards or by implication, the application of engineering judgment or studies in applying those Standards. The deletion of the Guidance language from Section 1A.09 of the 2009 MUTCD did not change that. Further, the added sentence of the definition of Standard 1A.13 was intended as a clarification and was not intended to change the meaning of Standard or remove the application of engineering judgment or studies in applying Standards where the language of a particular Standard explicitly or implicitly requires it.

Accordingly, it is our Official Interpretation of Sections 1A.09 and 1A.13 that:

For recordkeeping purposes, we have assigned the following official interpretation number and title: "1(09)-1 (I) — Definition of Standard Statement." Please refer to this number in any future correspondence regarding this topic.

I trust this will clarify the intent and eliminate any confusion that has developed as a result of the wording of the added sentence in the definition of Standard and the elimination of certain Guidance in Section 1A.09 of the 2009 MUTCD. Please contact Mr. Hari Kalla at if you have any further questions concerning this matter. We also encourage individual agencies to bring to our attention any specific Standards that might need further clarification.