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Incoming Interpretation Letter 4-376(I) - RRFB Overhead Mounting

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Incoming E-mail

From: Rick Perez []

Sent: Tuesday, November 10, 2009 1:26 PM

To: Scott Wainwright (FHWA)

Subject: RRFB Interpretation


Based on the success of our first installation of Rectangular Rapid Flashing Beacons and ongoing concerns with pedestrian safety in another corridor, I am anticipating City Council approval to install 2 new RRFB's, and possibly more. However, the two new locations have issues with near-side bus stops (with 9 buses per hour) that preclude sight distance of right-side signage at the crossing itself, and I am reluctant to install supplemental RRFB's in the median refuge islands because they are relatively narrow (6 and 7 feet, respectively) and have a history (albeit limited, since they've only existed for 3 years) of knockdowns for median-mounted signs.

The Interim Approval suggests advance supplemental RRFB's (conditions 2d), but due to high entering volumes from an intersection immediately upstream in one case, and a relatively tight horizontal curve upstream in the other, I believe a mast arm installation of the RRFB would be a superior solution. However, this would preclude the required use of the W16-7p.

If I want to pursue the mast arm installation, is this e-mail sufficient to apply for an interpretation to allow it? Do I need a more formal submittal? Or does this a require a separate request for experimentation?

Here are links to the locations in question:,+98003&sll=37.020098,-95.712891&sspn=33.106276,56.337891&ie=UTF8hq=&hnear=S+324th+St+%26+17th+Ave+S&ll=47.312009,-122.310987&spn=0,359.998281&t=h&z=19&lci=transit&layer=c&cbll=47.31164,-122.310995&panoid=eeSTB_1ZoLj3r36R9Z_gQQ&cbp=12,175.26,,0,5,+98003&sll=37.020098,-95.712891&sspn=33.106276,56.337891&ie=UTF8hq=&hnear=S+324th+St+%26+17th+Ave+S&ll=47.3116,-122.30643&spn=0,359.998281&t=h&z=19&lci=transit&layer=c&cbll=47.311594,-122.306293&panoid=zqjz6e-ghbnD4owDjrP5ug&cbp=12,117.65,,0,5

I would appreciate your guidance.

Rick Perez, P.E.
City Traffic Engineer
City of Federal Way
33325 8th Ave S
PO Box 9718
Federal Way, WA 98063
253-835-2709 fax

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