Pedestrian Safety Guide and Countermeasure Selection System


A Rectangular Rapid-Flashing Beacon (RRFB) in Princeton, New Jersey. Federal Highway Administration.

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




Rectangular Rapid-Flashing Beacon (RRFB)

RRFBs are pedestrian-actuated conspicuity enhancements used in combination with a pedestrian, school, or trail crossing warning sign to improve safety at uncontrolled, marked crosswalks. The device includes two rectangular-shaped yellow indications, each with an LED-array-based light source, that flash with high frequency when activated. The RRFB design differs from the standard flashing beacon by utilizing:

  • A different shape
  • A much faster rapid-pulsing flash rate.
  • A brighter light intensity.

The RRFB is a treatment option at many types of established pedestrian crossings. RRFBs are particularly effective at multilane crossings with speed limits less than 40 mph. Consider the Pedestrian Hybrid Beacon (PHB) instead for roadways with higher speeds.

RRFBs are placed on both sides of a crosswalk below the pedestrian crossing sign and above the arrow indication pointing at the crossing. The flashing pattern can be activated with pushbuttons or automated (e.g., video or infrared) pedestrian detection, and should be unlit when not activated.

The Federal Highway Administration has issued interim approval for the use of the RRFB (IA-21). State and local agencies must request and receive permission to use this interim approval before they can use the RRFB.


The RRFB is a device used in combination with pedestrian warning signs to provide a high-visibility strobe-like warning to drivers when pedestrians use a crosswalk.


• RRFBs should not be used without the presence of a pedestrian crossing sign.
• A RRFB should be installed in the median rather than the far-side of the roadway if there is a pedestrian refuge or other type of median.
• Advance yield or stop pavement markings and signs may be used to supplement RRFBs.
• The crosswalk approach should not be controlled by a YIELD sign, STOP sign, traffic-control signal, or located at a roundabout.
• 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 RRFB treatments may diminish their effectiveness.
• Other treatments may be more appropriate in locations with sight distance constraints.
• A high-intensity unit (SAE-1) should be used instead of a less intense unit.

Estimated Cost

Min. Low
Max. High
Cost Unit
# of Sources (Observations)
Flashing Beacon

The cost to furnish and install a flashing beacon can vary widely depending on site conditions and the type of device that is used (from $4,500 to $52,000 each). 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 message 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.

Safety Effects

The installation of RRFBs can reduce pedestrian crashes by 47%, see NCHRP Research Report 841: Development of Crash Modification Factors for uncontrolled Pedestrian Crossing Treatments.

Case Studies

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