COVID-19: Transportation Response Center
Active warning beacons are user-actuated amber flashing lights that supplement warning signs at unsignalized intersections or mid-block crosswalks. Beacons can be actuated either manually by a push-button or passively through detection. Rectangular Rapid Flash Beacons (RRFBs), a type of active warning beacon, use an irregular flash pattern similar to emergency flashers on police vehicles and can be installed on either two-lane or multi-lane roadways. Active warning beacons should be used to alert drivers to yield where bicyclists have the right-of-way crossing a road.
Click on the images below to view 3D concepts of rectangular rapid flash beacons.
“The RRFB offers significant potential safety and cost benefits, because it achieves very high rates of compliance at a very low relative cost in comparison to other more restrictive devices that provide comparable results, such as full midblock signalization.”
Federal Highway Administration. (2008). Interim Approval for Optional Use of Rectangular Rapid Flashing Beacons (IA-11).
“Overall, motorist yielding increased from 2% before to 35% after. When the flasher was activated, motorist yielding was 54%.”
Hunter, W. W., Srinivasan, R., Martell, C. (2009). Evaluation of the Rectangular Rapid Flash Beacon at a Pinellas Trail Crossing in St. Petersburg, Florida. Florida Department of Transportation.
“With the introduction of a two- and four-beacon system came increases of 70.6% and 77.8% increases over baseline, respectively, and increases of 66% and 73.2% over the standard-beacon efficacy.”
Houten, R. V., Malenfant, L. (Undated). Efficacy of Rectangular-shaped Rapid Flash LED Beacons.
Federal Highway Administration. (2009). Manual on Uniform Traffic Control Devices.
Several municipalities and counties in the United States have experimented with and evaluated RRFBs for bicycles (as well as pedestrians), including the following:
Adapted from the Urban Bikeway Design Guide, published by Island Press.