Bicycle Safety Guide and Countermeasure Selection System


A RRFB used in combination with pedestrian warning signs, to provide a high-visibility strobe-like warning to drivers when pedestrians use a crosswalk. Flickr - Steven Vance

Photo by Carol Kachadoorian A Rectangular Rapid Flashing Beacon.
Photo by Carol Kachadoorian




Rectangular Rapid-Flashing Beacons (RRFB)

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

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

This device is currently not included in the Manual on Uniform Traffic Control Devices (MUTCD), but design, placement, and operation of RRFBs should be in accordance with FHWA's Interim Approval for Optional Use of Pedestrian-Actuated Rectangular Rapid-Flashing Beacons at Uncontrolled Marked Crosswalks, which was issued March 20, 2018. The interim approval for this device allows for usage as a warning beacon to supplement standard pedestrian and school crossing warning signs and markings at either a pedestrian, school, or shared-use path crossing.

Rectangular Rapid Flashing Beacons are placed on both sides of the roadway at an uncontrolled crosswalk below the pedestrian crossing sign and above the arrow plaque 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 median 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 or bicycle 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 message instructing users 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 U.S. 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.


The Rectangular Rapid-Flashing Beacon (RRFB) is a device using LED flashing beacons in combination with pedestrian and bicycle warning signs, to provide a high-visibility strobe-like warning to drivers when pedestrians and bicyclists 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 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

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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.

Safety Effects

National Cooperative Research Program Report 841 documents the safety benefits of Rectangular Rapid-Flashing Beacons.


To view references for this countermeasure group click here.

Case Studies

St. Petersburg, Florida