Understanding the New Inclusion of RRFB Guidelines in the MUTCD’s 11th Edition

The 11th Edition of the Manual on Uniform Traffic Control Devices (MUTCD), published on December 19, 2023, marks a significant milestone in traffic control and pedestrian safety with the inclusion of Rectangular Rapid Flashing Beacons (RRFBs). This groundbreaking update underscores the commitment to enhancing pedestrian safety across uncontrolled crosswalks. 

RRFBs, known for their distinct flashing pattern, have proven effective in increasing driver awareness and yielding behavior, thereby reducing pedestrian-related crashes at uncontrolled marked crosswalks. Their formal recognition in the MUTCD paves the way for broader adoption and represents a major leap forward in improving safety and accessibility for pedestrians. 

RRFBs were first introduced as an experimental device in the MUTCD in 2008 and, with the exception of a few months in early 2018 where this status was rescinded due to a patent issue, have remained under an interim approval. With the long-awaited release of the 11th Edition of the MUTCD, the RRFB is now a formal device.

Discover below a brief overview of RRFBs as well as how these beacons have been integrated into the MUTCD’s 11th Edition traffic control guidelines, their design innovations, and operational standards, all of which contribute to a safer and more pedestrian-aware roadway environment.

The Essentials of RRFBs

Rectangular Rapid Flashing Beacons (RRFBs) have been proven to be an extremely effective device for improving safety of pedestrians and cyclists at uncontrolled marked crosswalks. Here is an overview of their design, function, and impact on safety:

Design and Concept

  • RRFBs consist of two yellow, rectangular-shaped LED indicators that flash rapidly when activated.
  • They are typically post mounted and positioned on both the left-hand and right-hand side of the crosswalk. For typical two-way roadway applications, the RRFB lightbars are usually mounted back-to-back on each pole.
  • Suitable for various settings such as crosswalks at uncontrolled intersections, mid-block crosswalks, trail crossings, crosswalks with median islands, and crosswalks at roundabouts.


  • Activated by pedestrians or cyclists at uncontrolled marked crosswalks.
  • Emit intense, rapid flashes, ensuring visibility under various lighting conditions, including bright daylight.


  • The vast majority of RRFBs are solar powered, which enables a cost effective installation as connections to the power grid for each pole are avoided.
  • RRFB devices are wirelessly connected to one another, so that when any push button at the crosswalk is pressed all RRFBs will start flashing immediately and stop flashing at the same time.

Safety Impact

  • Enhances driver awareness – The distinct flashing pattern stands out, alerting drivers to the presence of crossing pedestrians or cyclists.
  • Increases driver compliance – Research indicates RRFBs can increase motorist yielding rates by up to 98%.
  • Reduced Crash Rates – Extensive research has proven that RRFBs can reduce pedestrian crashes up to 47%.
  • Protects vulnerable road users – Especially effective for ensuring the safety of young, elderly, or disabled pedestrians and cyclists.

MUTCD 11: Chapter 4L Overview

The inclusion of Rectangular Rapid Flashing Beacons (RRFBs) in the Manual on Uniform Traffic Control Devices (MUTCD) 11th Edition, specifically in Chapter 4L, marks a significant advancement in road safety regulations. 

Firstly, this inclusion sets a national standard, ensuring uniformity and consistency in the implementation of RRFBs across the United States. Secondly, by formally integrating RRFBs into the MUTCD, it elevates these devices from the interim, experimental status to a recognized tool. This move not only standardizes their use but also encourages wider adoption and adherence to best practices in protecting vulnerable road users.

This chapter of the MUTCD provides comprehensive standards and guidelines for the installation, design, and operation of RRFBs. Here is a summary of its key points:

Application of RRFBs (Section 4L.01)

  • RRFBs are specifically for pedestrian-activated and/or bicyclist-activated use at marked crosswalks on uncontrolled approaches.
  • RRFBs can be used at crosswalks at roundabouts, and at intersections with two crosswalks on an uncontrolled approach.

Installation Standards

  • RRFBs are required to function as a supplement to the following specific signs: W11-2 (Pedestrian), S1-1 (School), or W11-15 (Trail) crossing warning signs.
  • RRFBs can be used on an approach in advance to the crosswalk, providing it is supplemental to, and not a replacement for, the RRFBs at the crosswalk itself. 

Design Specifications (Section 4L.02)

  • Each RRFB unit shall comprise of two rapidly-flashed, rectangular-shaped yellow indications that flash to the specific flash pattern detailed in this section.
  • The indications must be at least 5 inches wide and 2 inches high, aligned horizontally with a minimum space of 7 inches between them.
  • The placement of RRFB units should be in direct conjunction with the associated crossing warning signs, either on the same support or directly above/below the sign for post-mounted or overhead-mounted signs, respectively.

Operational Standards (Section 4L.03)

  • RRFBs must remain normally dark and only activate upon pedestrian actuation, ceasing operation after a predetermined time.
  • All associated RRFB units for a given crosswalk must commence and cease their rapid flashing simultaneously.
  • The flash rate and sequence are specifically defined to maximize visibility while avoiding frequencies that might induce seizures.

Additional Considerations

  • The light intensity of the RRFBs during daytime must meet or exceed the minimum specifications for SAE J595 Class 1 yellow peak luminous intensity.
  • To avoid excessive glare during nighttime automatic dimming  may be utilized.

Guidance for Enhanced Accessibility

  • The use of audible information devices with RRFBs is recommended to assist pedestrians with vision disabilities.
  • Small lights directed at pedestrians in the crosswalk may be integrated into the RRFB or pedestrian push button detector for operational confirmation.

This overview of MUTCD 11: Chapter 4L highlights the guidelines and standards set specifically for the implementation of RRFBs. These specifications ensure that RRFBs are used effectively and consistently across various locations, thereby enhancing the safety and visibility of pedestrian and cyclist crossings.

Why Choose Availed Technologies’ AV-400 RRFB?

Availed Technologies’ AV-400 Series RRFB meets and exceeds MUTCD standards and provides industry-leading installation simplicity. The AV-400 is purpose-built exclusively for the RRFB application, and provides numerous features to simplify the installation and reduce installation time and cost. Additionally, the AV-400’s capacity for over 300 daily activations surpasses the typical usage requirements of even busy crosswalks.

The ultra-efficient design of the AV-400 accomplishes this high operating capacity with a compact, lightweight solar engine that is very easy to handle and is small enough to be suitable for installation on standard sign posts.  The AV-400 solar engine and lightbars come with universal mounting brackets that readily mount to all pole types.

Availed Technologies’ AV-400 Series RRFBs are designed for efficiency and effectiveness:

  • Solar Engine and Battery – 20W high-efficiency monocrystalline solar panel with 45° tilt and 360° rotation, 12V 14-18 Ah AGM sealed lead acid battery.
  • Performance – Exceeds MUTCD light output requirements by up to five times, rated for over 300 activations per day.
  • Wireless Network – 2.4 GHz wireless mesh, 10 channels, 1000′ range, synchronized activation under 150ms.
  • Environmental Tolerance – Operates in -40 to 165° F, battery works in -40 to 140° F, compliant with NEMA TS 2 standards.
  • Installation – Quick and simple, with a pre-wired post-top solar engine assembly and a factory-installed universal mounting bracket.

If you are looking for more information on the use and installation of the AV-400 RRFB please visit our FAQ page.

Your MUTCD-Compliant RRFB Solution

The inclusion of RRFBs in the MUTCD’s Chapter 4L is a pivotal moment for road safety, acknowledging their importance in traffic management. This standardization is a major step in unifying safety practices nationwide.

By partnering with Availed Technologies, you’ll benefit from the AV-400 RRFB, an industry-leading product that adheres to MUTCD standards. Start your journey towards safer crosswalks by reaching out to us, and let us collaboratively enhance road safety.

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Exploring the Impact of Rectangular Rapid Flashing Beacons in Rural and Small Communities

In a world increasingly concerned with road safety, Rectangular Rapid Flashing Beacons (RRFBs) have gained attention as a pivotal technology designed to protect pedestrians, cyclists and other vulnerable road users in uncontrolled marked crosswalks. Much of the existing research on RRFBs has been limited to urban environments, leaving a noticeable gap in our understanding of their effectiveness in rural and smaller communities. 

A recent comprehensive study by the University of Vermont in association with the Vermont Agency of Transportation, “Effectiveness of Rectangular Rapid Flashing Beacons (RRFBs) in Small and Rural Communities,” addresses this gap. The study not only affirms the effectiveness of RRFBs in rural settings but also provides key insights for best installation practices. These findings are integral to Availed Technologies’ approach to the design and manufacturing of RRFBs, further reinforcing why Availed is an industry leader.

A Deep Dive into the Study’s Findings

The University of Vermont’s research employed a rigorous methodological approach that included a controlled before-and-after study design and in-depth video analysis. The outcomes were promising: RRFBs led to an improvement in driver compliance and overall road safety in rural Vermont. There were noticeable improvements in driver yielding behavior and reductions in pedestrians crossing outside of designated crosswalks. Pedestrian wait times at crossings also decreased.

Additionally, the study points out that installations in Montpelier, which used different LED lights and are not considered RRFBs, showed less effectiveness compared to other locations. This only strengthens the case for RRFBs as an optimal choice for pedestrian safety solutions.

Furthermore, the study discovered that the effectiveness of RRFBs was consistent, not just in central locations but also in transitional zones between rural and urban areas. This all-encompassing effectiveness is crucial because it shows that RRFBs are not just a ‘one-size-fits-all’ urban solution but a versatile tool for smaller communities and lower pedestrian volume locations.

Design Features and Considerations

This study on RRFBs underscored the importance of thoughtful design features to enhance their effectiveness, especially in adherence to Americans with Disabilities Act (ADA) requirements. Features like tactile arrows and audio cues can help visually impaired individuals navigate crossings safely. Additionally, the study highlighted the need for flexible power options like solar, which is particularly useful in rural areas where electrical grid access may be limited.

The angle and intensity of the flashing lights were also identified as critical design factors. Lights need to be bright enough to attract drivers’ attention from a distance, but not so intense as to impair vision. This balance is especially crucial in varying weather conditions often encountered in rural settings. Moreover, RRFBs should be durable enough to withstand the gamut of environmental conditions, ensuring that maintenance needs are minimized.

Availed Technologies’ focus on advanced design features—including ADA-compliant push buttons, high capacity solar-powered systems, and robust field adjustable RRFB lightbars —makes us an industry leader. These features enable the RRFBs to function optimally in all conditions, ensuring the highest level of road safety for rural communities.

Factors Influencing RRFB Effectiveness

While the study provided an overwhelmingly positive outlook on the role of RRFBs in rural safety, it also illuminated how different factors could affect their effectiveness. These factors include the time of day, the day of the week, and even the type of road users, such as cyclists and runners. Such granular data is invaluable for planners and policymakers who aim to deploy RRFBs most effectively, further underscoring the vital role played by high-quality RRFBs like those manufactured by Availed Technologies.

This is critical because these factors are directly linked to road safety. In particular, the study found that the installation of RRFBs led to improvements in driver compliance ranging from 12% to 43%, showcasing the tangible benefits of these devices. Pedestrian wait times also improved, with reductions ranging from 0.8 to 2.6 seconds at two of the RRFB locations studied.

The Global Relevance of RRFBs

Although the study is rooted in the specific context of Vermont, its findings have broader implications. Rural and small communities across the nation and indeed, around the world, share similar characteristics. The issue of road safety is universal, and the research strongly indicates that RRFBs, when implemented correctly, can be an effective solution for a range of settings.

Making Roads Safer with Availed Technologies’ RRFBs

As the study results indicate, not all RRFBs are created equal. Availed Technologies distinguishes itself by offering RRFBs that not only meet but exceed compliance and safety standards. With our products, communities—be they large or small, urban or rural—can achieve remarkable improvements in pedestrian safety and driver compliance.

Availed’s RRFBs are not just built to meet the basic standards; they exceed them. Our attention to detail ensures maximum visibility and durability, two key factors that are even more crucial in rural settings where regular maintenance may be less frequent. In addition, Availed’s RRFBs are adaptable and can be installed in a variety of roadway conditions, a feature highlighted as beneficial in the study.

As we strive for safer roads for all, there’s no better partner than Availed Technologies to provide RRFB solutions. Grounded in scientific research and committed to quality and safety, Availed’s RRFBs are the best pedestrian safety solution for communities large and small. Your community deserves the best, and the best is Availed Technologies’ AV-400 RRFB.


Contact Us to Learn More!

Crosswalk with two Availed RRFB poles on a sunny day. A castle-like house stands majestically in the background.

Specifying RRFBs – The Essentials

This article provides the essential Performance Requirements to include when specifying Rectangular Rapid Flashing Beacons (RRFBs).

Here at Availed Technologies, we work with municipalities and engineering firms across North America everyday who are in the process of specifying RRFBs. We focus on the following three points: Array to Load Ratio, Autonomy, and Shading.

Before we get into the performance requirements it should be noted that the operational requirements of an RRFB are important to specify and these are clearly defined in the MUTCD 11th Edition, Chapter 4L. One other point that is discussed at the end of this article is the option to use standard sign posts for RRFBs.

#1: RRFBs and Array to Load Ratio

The Array to Load Ratio is the power coming into the system divided by the power consumed by the system. It is the single most important metric to pay attention to when specifying Solar RRFBs. The ALR Ratio must be greater than 1:1, and a minimum of 1.2:1 is recommended. Regardless of the size of the solar panel or size of the battery, a system with an ALR of less than one means there is a power deficit and the system will run out of power eventually.

For Solar RRFBs, the ALR must be calculated using worst case conditions to ensure reliable year-round operation. This is typically in December when the solar energy available is at a minimum. The Solar insolation for a particular location is available through a comprehensive database from NREL that is based on historical information which accounts for prevailing weather conditions and latitude.

Factoring in the site-specific solar data, the daily power generated by the RRFB is determined by how the device converts the available solar energy into electrical energy that runs the system and is stored in the battery. This calculation is manufacturer-specific and varies significantly from one brand to another.

Power Consumed By RRFBs

The power consumed by the RRFB is also very manufacturer-specific and will vary even more from brand to brand than the power generation side of the equation. Power is consumed by the RRFB lightbars when they flash and also by the wireless connection between the systems which manages the activation of all systems at the crosswalk, so that when any one push button is pressed all the RRFBs start flashing immediately and stop flashing at the same time.

The wireless connection must always be ‘on’ and therefore this function is a significant portion of the power consumed. Advances in both LED and wireless technology have enabled dramatic improvements in power efficiency, the result of which is the ability to achieve a high ALR with a compact and lightweight system.

#2: RRFBs and Autonomy

The autonomy of an RRFB is defined as the number of days it can operate without any charging. It is a function of the daily power consumption and the battery capacity of the system. In an actual installation autonomy is hypothetical because the system will charge in the day even during cloudy conditions. Cold temperatures will decrease the battery capacity and this should be factored into an autonomy calculation.

Autonomy should never be the sole metric used in specifying a solar RRFB because it does not take into account the ‘power in’ of the system. Nevertheless, it is an important consideration as energy storage is essential for the system to function during nighttime and low light conditions. An autonomy of 5-10 days is recommended.

#3: RRFBs and Shading

Shading from trees and buildings is site specific and is often overlooked. At Availed Technologies, we can review the location with Google street view and we will incorporate this information when producing the solar performance report.

Key takeaways:

  • Always use ALR and Autonomy when specifying RRFBs
  • Use a solar performance report that factors in site specific shading to ensure system reliability
  • Never specify the solar panel size or battery capacity alone as these metrics do not factor in the power generation and power consumption of the system.

For further information on ALR, Autonomy, and RRFB efficiency see the article The Power of Solar RRFB Systems.

A final consideration when specifying RRFBs is the pole type. A positive benefit of an efficient system is that the product is compact and lightweight which makes it feasible to use standard sign posts. Using 2” Telespar square perforated tubing or standard 2” round sign posts will significantly reduce the installed cost of the system and will simplify the installation process. Standard sign posts can also be helpful for placement of RRFBs in locations where space is limited.

One feature worth mentioning regarding the Availed AV-400 RRFB is that it comes with a Universal mounting system that is compatible with all pole types, from the traditional 4 ½” diameter pedestal poles to 2” square and round posts, and everything in between.

Have any further questions about the essentials of RRFBs? Reach out to our team today!

Highlighter yellow Availed RRFB school crossing sign with arrow, with a tree and blue sky in background.

Availed Technologies Has Been Approved by Oregon DOT

We are happy to announce that the Availed AV-400 Rectangular Rapid Flashing Beacon is now listed as a qualified product on the Oregon DOT Green Sheets.

What is the Green Sheet Qualification Process?

Maintained by the Traffic-Roadway Section of the Oregon Department of Transportation, the Green Sheet Qualification process has a comprehensive evaluation process for a wide range of Traffic Signal, Illumination, and ITS equipment that includes physical, operational, and environmental testing.  For RRFBs in particular, the device is evaluated to ensure it is compliant with the requirements of the FHWA interim approval and the MUTCD and that it meets the requirements for mounting as shown in TM493.  Only prequalified RRFBs already listed on the green sheets will be approved for use for Oregon DOT projects under contract

The Importance of Energy Efficiency for RRFBs

As is very typical in the Pacific Northwest, many parts of Oregon have very low solar insolation during the winter months which presents a challenging environment for solar products such as the Availed AV-400 RRFB.  Key to ensuring reliable operation is energy efficiency, and this is where the AV-400 stands out.  All aspects of the product, from the wireless connectivity between units to the optical design of the LED lightbars has been designed to minimize power consumption.


For more about energy efficiency with RRFBs and how to specify products to ensure reliable operation see this article.


RRFBs in the Next MUTCD

Update: As of November 19, 2023, the 11th Edition of the MUTCD has been issued with the inclusion of RRFBs in Chapter 4L. Read more about it here.


RRFBs were first introduced under an interim approval with the Federal Highway Administration (FHWA) in 2008.  Since that time, and due to the high effectiveness of the device, the use of  RRFBs as a crosswalk enhancement has become widespread.

Today, we here at Availed Technologies are going to outline RRFBs proposed role in the next MUTCD– including the most significant proposed changes to it to enhance pedestrian safety.

Let’s jump right in:

The Absence of an Updated MUTCD

In the absence of an updated version of the Manual on Uniform Traffic Control Devices (MUTCD),  the RRFB has remained under an interim approval for well over a decade.  On March 4th, 2022 FHWA Issued a Status of Rulemaking for the Eleventh Edition of the MUTCD.

According to this update, The Infrastructure Investment and Jobs Act directs USDOT to update the MUTCD by no later than May 15, 2023.

As one would expect, RRFBs are a key feature of the recommended changes as noted in the FWHA, U.S. Department of Transportation (DOT) notice of proposed amendments (NPA). These recommended changes orbit around the incorporation of provisional traffic control devices.

The Incorporation of Provisional Traffic Control Devices

The incorporation of provisional traffic control devices currently under Interim Approval, including pedestrian-actuated rectangular rapid-flashing beacons at uncontrolled marked crosswalks, green-colored pavement for bicycle lanes, red-colored pavement for transit lanes, and a new traffic signal warrant based on crash experience.

It is also noteworthy that several other key proposed changes to the MUTCD focus on pedestrians and bicyclists, mainly:

  • Improvements to safety and accessibility for pedestrians, including the location of pushbuttons at signalized crosswalks, crosswalk marking patterns, and accommodations in work zones
  • Expanded traffic control devices to improve safety and operation for bicyclists, including intersection bicycle boxes,two-stage turn boxes, bicycle traffic signal faces, and a new design for the U.S. Bicycle Route sign

The National Committee on Uniform Traffic Control Devices (NCUTCD) recommended changes to the MUTCD are very similar to the Interim Approval (IA-21).  One significant addition is guidance on the use of RRFBs at intersections with two crosswalks on an uncontrolled approach.  Additional guidance is provided for the use of RRFBs with overhead-mounted signs.

The Role of RRFBs in the Future of Pedestrian Safety

Here at Availed Technologies, we have over 25 years of experience in the Solar LED industry. We understand that providing a best-in-class product demands the support of industry-leading partners, and we are very proud to be represented by some of the most trusted companies in the business.

We strongly encourage you to read more about the MUTCD proposed changes today– and, if you have any questions, to reach out to our team!