Pedestrian Safety Guide and Countermeasure Selection System


A Rectangular Rapid Flash Beacon (RRFB) used in combination with pedestrian warning signs, to provide a high-visibility strobe-like warning to drivers when pedestrians use a crosswalk. Source: Flickr - Steven Vance (2010)

Source: Carol Kachadoorian (2012) A Rectangular Rapid Flash Beacon (RRFB).
Source: Carol Kachadoorian (2012)




Rectangular Rapid Flash Beacon (RRFB)

The RRFB design differs from the standard flashing beacon by utilizing:

• A rapid flashing frequency (approximately 190 times per minute)
• Brighter light intensity
• Ability to aim the LED lighting

This device is currently not included in the MUTCD, but design, placement, and operation of RRFBs should be in accordance with FHWA’s Interim Approval for Optional Use of Rectangular Rapid Flashing Beacons issued July 16, 2008 ( The interim FHWA approval for this device allows for usage as a warning beacon to supplement standard pedestrian crossing warning signs and markings at either a pedestrian or school crossing.

Rectangular rapid-flash beacons are placed on both sides of a crosswalk below the pedestrian crossing sign and above the arrow indication pointing at the crossing. The crosswalk approach should not be controlled by a YIELD sign, STOP sign, traffic-control signal, or located at a roundabout. RRFBs should not be used without the presence of a pedestrian crossing sign. If there is a pedestrian refuge or other type of median, a beacon should be installed in the median rather than the far-side of the roadway. Advance yield or stop pavement markings and signs may be used to supplement RRFBs.

The flashing pattern can be activated with pushbuttons or automated (e.g., video or infrared) pedestrian detection, and should be unlit when not activated. Additionally, pauses can be incorporated at chosen intervals to create patterns and increase motorist recognition of accompanying information. The RRFB can be constructed using solar power to simplify installation. The installation may include an indication visible to pedestrians confirming that the device is activated and/or an audible mes¬sage instructing pedestrians to wait until cars have stopped before crossing. The pushbutton and other components of the crosswalk must meet all other MUTCD accessibility requirements.

RRFBs have been used on crosswalk signs in a number of locations around the United States including Boulder, Colorado, Washington, D.C. and St. Petersburg, Florida. These jurisdictions have tested the effectiveness of the device and the results indicate that this device increases motorist compliance to a much higher percentage than crosswalks without beacons or standard flashing beacons.14


The Rectangular Rapid Flash Beacon (RRFB) is a device using LED flashing beacons in combination with pedestrian warning signs, to provide a high-visibility strobe-like warning to drivers when pedestrians use a crosswalk.


• RRFB should supplement standard crossing warning signage and markings.
• Should not be used in conjunction with YIELD, STOP, or traffic signal control.
• Solar-power panels can be used to eliminate the need for a power source.
• RRFB should be reserved for locations with significant pedestrian safety issues, as over-use of RFB treatments may diminish their effectiveness.
• Other treatments may be more appropriate in locations with sight distance constraints.
• RRFBs are good for two-lane streets, but less well-suited for multi-lane roadways.
• A high-intensity unit (SAE-1) should be used instead of a less intense unit.

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Flashing Beacon

As a relatively new treatment, RRFBs have not been implemented extensively throughout this country, but are now becoming more prevalent in certain states and cities. The cost to furnish and install a flashing beacon can vary widely, depending on site conditions and the type of device that is used.

Safety Effects

A summary of studies that have looked at the safety effects of the rectangular rapid flash beacon can be found here.

Case Studies

San Francisco, California
St. Petersburg, Florida
Elmwood Park, New Jersey
Miami-Dade County, Florida