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Interpretation Letter 4(09)-5(I) - RRFB Use with W11-15 Sign

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DOT Logo

U.S. Department
of Transportation

Federal Highway

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

August 12, 2010

In Reply Refer To: HOTO-1

Mr. Pablo Para
Traffic Engineer
City of Auburn
25 West Main Street
Auburn, WA 98001-4998

Dear Mr. Para:

Thank you for your July 28 email to Mr. Scott Wainwright of our Manual on Uniform Traffic Control Devices (MUTCD) Team requesting an interpretation of certain technical conditions of Interim Approval IA-11 for Rectangular Rapid Flashing Beacons (RRFB) dated July 16, 2008. You asked whether it is allowable for RRFB to supplement W11-15 Combined Bicycle/Pedestrian (Trail) Crossing warning signs.

Several of the technical conditions of IA-11 indicate that RRFB are to be used only with W11-2 (Pedestrian Crossing) or S1-1 (School Crossing) warning signs. Subsequent to the issuance of IA-11, the final rule adopting the 2009 edition of the MUTCD was issued in December, 2009. Section 2C.49 of the 2009 MUTCD contains the new W11-15 warning sign and indicates that this new sign may be used where both bicyclists and pedestrians might be crossing the roadway, such as at an intersection with a shared-use path.

The new W11-15 sign is closely related to and performs the same function as the W11-2 sign. Therefore, it is our Official Interpretation that RRFB may be used to supplement a W11-15 sign at a shared-use trail crossing if the W11-15 substitutes for the W11-2 and is placed at the crosswalk.

Thank you for writing on this subject. We hope that our interpretations answer your questions. If you have any questions, please contact Mr. Wainwright by e-mail at or by telephone at 202 366 0857. Please note that we have assigned your request the following official interpretation number and title: "4(09)-5(I) - RRFB Use with W11-15 Sign." Please refer to this number in any future correspondence regarding this issue.

Sincerely yours,

Original signed by:

Hari Kalla for

Mark R. Kehrli
Director, Office of Transportation Operations