Understanding RRFB MUTCD guidelines and best practices

A rectangular rapid flashing beacon (RRFB) is an effective, low-cost solution for pedestrian safety, reducing crashes by 47% and increasing driver yield rates up to 96%.

Understanding RRFB MUTCD guidelines and best practices

A rectangular rapid flashing beacon (RRFB) is an effective, low-cost solution for pedestrian safety, reducing crashes by 47% and increasing driver yield rates up to 96%.

Pedestrian fatalities at uncontrolled crossings are increasing. The Federal Highway Administration (FHWA) recommends the RRFB as an effective countermeasure and has approved it in the Manual on Uniform Traffic Control Devices (MUTCD).

Part 1:
RRFB Effectiveness

Mid-block locations and uncontrolled crossings are common locations for pedestrian fatalities due to insufficient crossing opportunities and infrastructure. This presents a barrier to safe, convenient, and sustainable pedestrian networks.

6,283

The number of pedestrians killed every year in motor vehicle crashes.1

74%

The percentage of pedestrian fatalities that occur at non-intersections.1

17%

The percentage of people injured in traffic accidents that were pedestrians.1

18-28%

The effectiveness of crosswalk paint alone at stopping drivers when a pedestrian is present.2

We need an effective solution to ensure all multi-modal users stay safe.

A Proven Solution

The rectangular rapid-flashing beacon (RRFB) is a pedestrian-actuated traffic device that warns drivers of crossing pedestrians with high-intensity, rapid-flashing amber LED lights.
Solar-powered traffic beacons have fast become the preferred choice for crosswalks, school zones, and warning signs around the world. Why choose solar?
1. Looking for easy and low-cost installation
Solar requires no trenching for power, no metering, and can be installed by one or two people without extensive equipment.

2. Distance to existing electrical infrastructure
Trenching for AC can make a project prohibitively expensive. Solar can install almost anywhere without inhibiting traffic or damaging the landscape.

3. Sustainability initiatives are in place
Solar-powered beacons are an easy-to-implement way to achieve sustainability goals. The Federal Highway Administration (FHWA) also encourages solar beacons, where possible.

>> Learn more about solar

RRFBs' rapid flashing, rectangular beacons have been proven to be increase yield rates more than slower flashing, circular beacons. Why are they so effective?

RRFBs were designed to loosely mimic the visual effect of emergency vehicle lights like ambulances. RRFBs use higher intensity lights with a quick flash pattern, making then highly visible when competing with other traffic signals, headlight glare, or wet roads.

They use a wig-wag plus simultaneous (WW+S) flash pattern, as required by the FHWA, to quickly grab drivers’ attention.

solar rectangular rapid flashing beacon rrfb flashing with WW+S flash pattern

rrfb yield rates icon 150x150
Increase driver yield rates between
73-96%
rrfb yield rates icon 150x150
Reduces pedestrian crashes by
47%
0.53 crash modification factor (CMF)
rrfb yield rates icon 150x150
Increase driver yield rates between
$22,250

Let’s break down what the research has discovered about RRFB effectiveness.

Circular Beacons vs. RRFBs

An experiment in St. Petersburg, Florida, found that RRFBs increased driver yield rates significantly more than a standard circular flashing beacon.

Circular flashing beacons were only slightly more effective than marked crosswalks and warning signs.

Why the increase?

  • Different shape
  • Unique, rapid flashing pattern
  • Brighter intensity
rrfbs vs circular beacons graph

U.S. Department of Transportation Federal Highway Administration, Report No. FHWA-HRT-10-043, Effects of Yellow Rectangular Rapid-Flashing Beacons on Yielding at Multilane Uncontrolled Crosswalks

rrfbs in school zones graph

Technical Memorandum to City of Garland Department of Transportation, Before-and-After Study of the Effectiveness of Rectangular Rapid-Flashing Beacons used with School Sign in Garland, Texas

RRFBs in School Zones

An experiment in Garland, Texas, found that RRFBs installed in a school zone substantially increased driver yield rates.

Yield rates before RRFB installation were as low as 1% and less. After installation, they increased to 78% and 81%.

Long-term Effectiveness

Two experiments in St. Petersburg, Florida, reported that the safety effect of RRFBs on driver yield rates did not fall off after months of sustained use. In fact, some sites had higher yield rates 14 months after the initial test.

Experiment A

Researchers studied 4 RRFB sites and compared yield rates before and after installation, then repeated the test 14 months later.

long term rrfbs experiment a graph

U.S. Department of Transportation Federal Highway Administration, Report No. FHWA-HRT-10-043, Effects of Yellow Rectangular Rapid-Flashing Beacons on Yielding at Multilane Uncontrolled Crosswalks

Experiment B

This experiment evaluated RRFBs across 19 different sites on roads with a variety of lanes, traffic flow, and annual average daily traffic over the course of 2 years.

Researchers found significantly high driver yield rates sustained over the long-term.

long term rrfbs experiment b graph

U.S. Department of Transportation Federal Highway Administration, Report No. FHWA-HRT-10-043, Effects of Yellow Rectangular Rapid-Flashing Beacons on Yielding at Multilane Uncontrolled Crosswalks

Geographic Differences

RRFBs have been tested in a vast range of studies across the US and Canada, showing the same relative effect on driver yield rates.

rrfbs geographical differences graph

Circular Beacons vs. RRFBs

An experiment in St. Petersburg, Florida, found that RRFBs increased driver yield rates significantly more than a standard circular flashing beacon.

Circular flashing beacons were only slightly more effective than marked crosswalks and warning signs.

rrfbs vs circular beacons graph

U.S. Department of Transportation Federal Highway Administration, Report No. FHWA-HRT-10-043, Effects of Yellow Rectangular Rapid-Flashing Beacons on Yielding at Multilane Uncontrolled Crosswalks

Why the increase?

  • Different shape
  • Unique, rapid flashing pattern
  • Brighter intensity

RRFBs in School Zones

An experiment in Garland, Texas, found that RRFBs installed in a school zone substantially increased driver yield rates.

Yield rates before RRFB installation were as low as 1% and less. After installation, they increased to 78% and 81%.

rrfbs in school zones graph

Technical Memorandum to City of Garland Department of Transportation, Before-and-After Study of the Effectiveness of Rectangular Rapid-Flashing Beacons used with School Sign in Garland, Texas

Long-term Effectiveness

Two experiments in St. Petersburg, Florida, reported that the safety effect of RRFBs on driver yield rates did not fall off after months of sustained use. In fact, some sites had higher yield rates 14 months after the initial test.

Experiment A

Researchers studied 4 RRFB sites and compared yield rates before and after installation, then repeated the test 14 months later.

long term rrfbs experiment a graph

U.S. Department of Transportation Federal Highway Administration, Report No. FHWA-HRT-10-043, Effects of Yellow Rectangular Rapid-Flashing Beacons on Yielding at Multilane Uncontrolled Crosswalks

Experiment B

This experiment evaluated RRFBs across 19 different sites on roads with a variety of lanes, traffic flow, and annual average daily traffic over the course of 2 years.

Researchers found significantly high driver yield rates sustained over the long-term.

long term rrfbs experiment b graph

U.S. Department of Transportation Federal Highway Administration, Report No. FHWA-HRT-10-043, Effects of Yellow Rectangular Rapid-Flashing Beacons on Yielding at Multilane Uncontrolled Crosswalks

Geographic Differences

RRFBs have been tested in a vast range of studies across the US and Canada, showing the same relative effect on driver yield rates.

rrfbs geographical differences graph

Where RRFBs work best

Let’s break down what the research has discovered about RRFB effectiveness.
rrfbs for multilane crossings less than 40 mph 250x250

Multilane crossings with speed limits less than 40 mph

rrfbs for areas with safety concerns 250x250

Areas with critical safety concerns, such as pedestrian and school crossings

rrfbs for roadways with good sight

Roadways with good sight (i.e. not immediately after a curve)

The FHWA has synthesized research on RRFB effectiveness alongside other crosswalk safety countermeasures to create a selection matrix to help municipalities choose an appropriate treatment.

You can find the matrix as well as other tips for evaluating crosswalk safety countermeasures with FHWA’s Safe Transportation for Every Pedestrian (STEP) resource.

rrfb selection matrix legend
rrfb selection matrix

1

rio rancho, nm, carmanah rrfb case study image

Rio Rancho, NM, roadway
2 lanes, median present, < 9,000 AADT,
40 mph posted speed limit = RRFB recommended

2

everett, wa, carmanah rrfb case study image

Everett, WA, roadway
2 lanes, median present, < 15,000 AADT,
30 mph posted speed limit = RRFB recommended

Part 2:
MUTCD IA-21 Guidelines

RRFBs are not currently included in the MUTCD, however, the FHWA has issued an interim approval for its use. All RRFB installations must comply with the conditions detailed in the FHWA Interim Approval 21 (IA-21).

States and local agencies must request and receive permission to use this interim approval before they can use the RRFB.

RRFBs are also approved in Canada!

Beacon flashing

Flash pattern
The RRFB shall flash in a wig-wag plus simultaneous (WW+S) flash pattern.

rrfb wig wag plus simultaneous WW+S slow

Nighttime dimming
To minimize excessive glare at night, automatic signal dimming should be used.

rrfb dimming with text

Allowable uses

Allowed signs
The RRFB shall only be used to supplement the following post-mounted or overhead-mounted signage located at or immediately adjacent to an uncontrolled marked crosswalk:

rrfb mutcd requirements w11-2 sign
W11-2 pedestrian crossing sign
rrfb mutcd requirements s1-1 sign
S1-1 school zone crossing sign
rrfb mutcd requirements w11-15 sign
W11-15 bicycle / pedestrian crossing sign

Plaque
Pair signs with a W16-7P diagonal downward arrow plaque.

rrfb mutcd requirements w16-7p yellow plaque
rrfb mutcd requirements w16-7p fyg plaque

Prohibited signs
RRFBs shall not be used for crosswalks controlled by YIELD signs or STOP signs (except at roundabouts).

rrfb mutcd requirements prohibited r1-1 sign
R1-1 stop sign
rrfb mutcd requirements prohibited r1-2 signR1-2 yield sign

Beacon dimensions and mounting

Light bar dimensions
Each RRFB indication shall be a minimum of 5 inches wide by 2 inches high and aligned horizontally with a minimum space of 7 inches in between.

rrfb mutcd requirements light bar dimensions

Light bar mounting
An RRFB supplementing a post-mounted sign and plaque may be mounted either directly below the crossing warning sign (and above the plaque) or within 12 inches above it.

rrfb mutcd requirements light bar mounting

Pedestrian detection

Pushbutton signage
If pedestrian pushbutton detectors are used, a Push Button To Turn On Warning Lights (R10-25) sign shall be installed explaining the purpose and use of the pushbutton.

rrfb mutcd requirements pushbutton signage

Speech pushbutton
If a speech pushbutton message is used, a locator tone shall be provided, shall not use vibrotactile indications, and should speak ”Yellow lights are flashing” twice

rrfb mutcd requirements speech pushbutton

Mounting height

Sign mounting
The W16-7P plaque shall be mounted below the crossing sign and the RRFB light bar at a minimum of 7 feet from the bottom of the plaque to the sidewalk.

Pushbutton mounting
For ADA compliance, the pushbutton shall be installed at a height of approximately 3.5 feet and no higher than 4 feet.

rrfb mutcd requirements mounting height