Active Warning Beacon for Bike Route at Unsignalized Intersection

BILLINGS, MT

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.

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).

BEND, OR

ALEXANDRIA, VA

ST. PETERSBURG, FL (PHOTO: WWW.PEDBIKEIMAGES.ORG, DAN BURDEN)

Benefits

Offers lower cost alternative to traffic signals and hybrid signals.

Significantly increases driver yielding behavior at crossings when supplementing standard crossing warning signs and markings.

The unique nature of the stutter flash (RRFBs) elicits a greater response from drivers than traditional methods.

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.

ST. PETERSBURG, FL

Typical Applications

Usually implemented at high-volume pedestrian crossings, but may also be considered for priority bicycle route crossings.

At locations where bike facilities cross roads at mid-block locations or at intersections where signals are not warranted or desired.

At locations where driver compliance at bicycle crossings is low.

Required Features

Active warning beacons shall be installed on the side of the road. If center islands or medians exist, providing secondary installations in these locations marginally improves driver yielding behavior.

Beacons shall be unlit when not activated.

Recommended Features

If intended for use by bicyclists, push button actuation shall be provided, and should be located so bicyclists can activate the signal without dismounting. Push buttons should have a supplemental sign facing the bicyclist’s approach to increase visibility.

The MUTCD provides additional guidance on use of Rectangular Rapid Flash Beacons (RRFBs):

• RRFBs shall be used to supplement standard pedestrian and bicycle crossing signs and markings.

• RRFBs should not be used where the crosswalk approach is controlled by a yield sign, stop sign, or traffic-control signal.

• RRFBs can be used at a crosswalk at a roundabout.

Federal Highway Administration. (2009). Manual on Uniform Traffic Control Devices.

Modified from: Van Houten, R., Malenfant, J.E. L. (2008).
An Analysis of the Efficacy of Rectangular-shaped Rapid-Flash LED Beacons to Increase Yielding to Pedestrians Using Crosswalks on Multilane Roadways in the City of St. Petersburg, FL

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.

ST. PETERSBURG, FL

Maintenance

Depending on power supply, maintenance can be minimal. If solar power is used, RRFBs should run for years without issue.

Treatment Adoption and Professional Consensus

Several municipalities and counties in the United States have experimented with and evaluated RRFBs for bicycles (as well as pedestrians), including the following:

• Alexandria, VA

• Billings, MT

• Boulder, CO

• Las Cruces, NM

• Miami-Dade, FL

• Portland, OR

• Roswell, NM

• St. Petersburg, FL

• Teton County, ID

• Washington, DC

• Wilmington, NC