The Rectangular Rapid Flashing Beacon (RRFB) is back!

As you’re aware, the RRFB under Interim Approval 11 was rescinded in December due to patents issued and pending. The FHWA has been informed and has confirmed that the patents have been expressly abandoned, and the RRFB is once again eligible for provisional use through another Interim Approval. Please note that this is a NEW Interim Approval (IA-21), which has been updated to reflect more recent research and experience with the device.

UPDATE: Colorado's Use of Rectangular Rapid-Flashing Beacons

CDOT Traffic and Safety division submitted a statewide blanket request for Colorado agencies to be allowed to implement the IA-21 RRFB. FHWA HAS APPROVED COLORADO’S BLANKET REQUEST for statewide use of RRFB. This obtains approval for ANY local agency to also use RRFB on local streets and roads; i.e. they do not have to ask FHWA prior to use. This does NOT mean you have to implement it or allow it on roads in your jurisdiction, but If/when you chose to, you would not have to request permission from FHWA.

Please do bear in mind that there are some conditions on this:

  1. CDOT must maintain a list of locations where RRFB are installed, both on CDOT and local system. Please send this information to KC Matthews at CDOT:

  2. See conditions included in Colorado’s request letter below. Basically, if perchance the Approval were rescinded again and/or not included in the next MUTCD update and/or they are found to pose a safety concern, you would have to remove the devices.

Small print aside - this is great news and a victory for safety!

NEW Interim Approval 21 - Rectangular Rapid-Flashing Beacons at Crosswalks

Q&A for Rectangular Rapid-Flashing Beacons (RRFB)
The MUTCD Team has also provided RRFB related Q and A's, which can be found online here: RRFB Q&A

Informational Brief on Treatments
For reference, FHWA has provided an Informational Brief: Treatments for Uncontrolled Marked Crosswalks that comply with the MUTCD to help practitioners select the most appropriate treatment(s) for the site conditions.

Colorado Letter