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FHWA Home / Safety / Proven Safety Countermeasures / Rectangular Rapid Flashing Beacons (RRFB)

Rectangular Rapid Flashing Beacons (RRFB)

A marked crosswalk or pedestrian warning sign can improve safety for pedestrians crossing the road, but at times may not be sufficient for drivers to visibly locate crossing locations and yield to pedestrians. To enhance pedestrian conspicuity and increase driver awareness at uncontrolled, marked crosswalks, transportation agencies can install a pedestrian actuated Rectangular Rapid Flashing Beacon (RRFB) to accompany a pedestrian warning sign. RRFBs consist of two, rectangular- shaped yellow indications, each with a light-emitting diode (LED)-array-based light source.1 RRFBs flash with an alternating high frequency when activated to enhance conspicuity of pedestrians at the crossing to drivers.

For more information on using RRFBs, see the Interim Approval in the Manual on Uniform Traffic Control Devices (MUTCD).1


The RRFB is applicable to many types of pedestrian crossings but is particularly effective at multilane crossings with speed limits less than 40 miles per hour.2 Research suggests RRFBs can result in motorist yielding rates as high at 98 percent at marked crosswalks, but varies depending on the location, posted speed limit, pedestrian crossing distance, one- versus two-way road, and the number of travel lanes.3 RRFBs can also accompany school or trail crossing warning signs.

RRFBs are placed on both sides of a crosswalk below the pedestrian crossing sign and above the diagonal downward arrow plaque pointing at the crossing.1 The flashing pattern can be activated with pushbuttons or passive (e.g., video or infrared) pedestrian detection, and should be unlit when not activated.


Agencies should:2

  • Install RRFBs in the median rather than the far-side of the roadway if there is a pedestrian refuge or other type of median.
  • Use solar-power panels to eliminate the need for a power source.
  • Reserve the use of RRFBs for locations with significant pedestrian safety issues, as over-use of RRFB treatments may diminish their effectiveness.

Agencies shall not:2

  • Use RRFBs without the presence of a pedestrian, school or trail crossing warning sign.
  • Use RRFBs for crosswalks across approaches controlled by YIELD signs, STOP signs, traffic control signals, or pedestrian hybrid beacons, except for the approach or egress from a roundabout.


1. MUTCD Interim Approval 21 - RRFBs at Crosswalks.

2. ”Rectangular Rapid Flash Beacon“ in PEDSAFE: Pedestrian Safety Guide and Countermeasure Selection System. FHWA, (2013).

3. Fitzpatrick et al. ”Will You Stop for Me? Roadway Design and Traffic Control Device Influences on Drivers Yielding to Pedestrians in a Crosswalk with a Rectangular Rapid-Flashing Beacon.“ Report No. TTI-CTS-0010. Texas A&M Transportation Institute, (2016).

4. NCHRP Research Report 841 Development of Crash Modification Factors for Uncontrolled Pedestrian Crossing Treatments, (2017).

Safety Benefits:

RRFBs can reduce crashes up to:


for pedestrian crashes.4

RRFBs can increase motorist yielding rates up to:


(varies by speed limit, number of lanes, crossing distance, and time of day).3

Photo: This photograph shows use of a rectangular rapid flashing beacon at a trail crossing. The crossing features a high visibility crosswalk and tactile curb ramp in the foreground of the image. The center of the image focuses on a W11-15 combined bicycle/pedestrian warning sign with rectangular rapid flashing beacon and W16-7P directional arrow plaque underneath. Below the warning sign assembly is a crosswalk button with instructional plaque.

RRFBs used at a trail crossing. Source: LJB

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Page last modified on November 19, 2021
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