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Interpretation Letter 2(09)-28 (I) - Curve Sign for 30 mph Speed Limit

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U.S. Department of Transportation
Federal Highway Administration

1200 New Jersey Avenue, SE.
Washington, D.C. 20590

March 6, 2012

In Reply Refer To: HOTO-1

Fred M. Greenberg, P.E.
Director of Traffic Services
BL Companies
355 Research Parkway
Meriden, CT 06450

Dear Mr. Greenberg:

Thank you for your of December 1, 2011, letter requesting an official interpretation of the Manual on Uniform Traffic Control Devices (MUTCD) concerning the use of the Curve (W1-2) sign in lieu of the Turn (W1-1) sign when the posted speed limit is 30 mph.

As you mentioned in your letter, Section 2C.07, paragraph 02, of the MUTCD states that "A Turn (W1-1) sign shall be used instead of a Curve sign in advance of curves that have advisory speeds of 30 mph or less." Your letter stated that in this particular case, the posted speed is 30 mph and the engineering study determined the advisory speed to be 30 mph. Even though the advisory speed is the same as the posted speed, and therefore you are not installing an Advisory Speed Plaque, the 30 mph threshold as stated in Section 2C.07 still applies. Therefore, the Turn (W1-1) sign shall be used instead of the Curve (W1-2) sign for the condition you describe.

We have numbered and titled this Official Interpretation as "2(09)-28 (I) - Curve Sign for 30 mph Speed Limit." If you have further questions on this matter, please contact Mr. Eric Ferron of our MUTCD Team at 720-963-3206 or

Sincerely yours,

Original signed by:

Mark R. Kehrli
Director, Office of Transportation Operations