Rectangular Rapid Flashing Beacon (RRFB)

DEFINITION AND DESCRIPTION

Rectangular Rapid Flashing Beacons (RRFBs) accompany pedestrian warning signs and improve awareness of marked crosswalks on uncontrolled approaches. RRFBs consist of two rectangular-shaped yellow indications, each with a light-emitting diode (LED)-array-based light source. RRFBs display alternating high frequency flashes when activated. They can be activated with pushbuttons or passively (e.g., video or infrared pedestrian detection) and should remain unlit when not activated.

RRFBs can reduce pedestrian crashes up to 47% and increase motorist yield rates up to 98% (CMF ID 9024).

Implementation Categories

Area(s) HSIP, Traffic Operations
Safety Category 4

CONSIDERATIONS

  • Use RRFBs at locations with high pedestrian volumes.
  • Except for roundabouts, do not use at controlled intersections.
  • Refer to Chapter 4L in the MUTCD for more information on RRFBs.
  • RRFBs can be powered with solar panels.

APPLICATION

  • RRFBs are an option at many types of pedestrian crossings, but they are most effective at multilane crossings with speed limits < 40 mph (FHWA).
  • Place RRFBs on both sides of a crosswalk below pedestrian crossing signs and above the diagonal downward arrow plaques that point to the crossing. 

example

Image Source: Google Earth

Complimentary Countermeasures

  • High-Visibility Crosswalks

REFERENCES AND RESOURCES

Federal Highway Administration. Proven Safety Countermeasures. https://highways.dot.gov/safety/proven-safety-countermeasures/rectangular-rapid-flashing-beacons-rrfb#:~:text=Agencies%20shall%20not%3A&text=Use%20RRFBs%20without%20the%20presence,or%20egress%20from%20a%20roundabout.

Federal Highway Administration. Manual on Uniform Traffic Control Devices for Streets and Highways (MUTCD), Federal Highway Administration, U.S. Department of Transportation, Washington DC, 2023.  https://mutcd.fhwa.dot.gov/kno_11th_Edition.htm

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CONTACT:

Chris VanDyke

Research Scientist | Program Manager

chrisvandyke@uky.edu