FHWA Rescission of Interim Approval of Rectangular Rapid Flashing Beacons
UPDATE: On March 20, 2018, the FHWA released a new Interim Approval 21 for Rectangular Rapid Flashing Beacons (RRFBs) as a tool to enhance pedestrian crossings. Learn more about the new interim approval and what it means in Alta Planning + Design’s memorandum.
On December 21, 2017, FHWA issued a memo rescinding its interim approval for the use of Rectangular Rapid Flashing Beacons (RRFBs). This news is alarming to the entire municipal and transportation industry as RRFBs have demonstrated many safety benefits (including a crash modification factor of 0.526) and have been found to be applicable over a wide range of roadway contexts to make crossings safer and more comfortable for people walking and biking alike.
So, now what?
This is the question that is being asked by many and discussions have abounded since the release of the memo. What is clear is that the dust has not yet settled on this decision. Entities like APBP, ITE, and NACTO are weighing in. This week is the annual TRB conference in Washington, DC, and we are sure this topic is being discussed ad nauseam.
Over the last week, technical email lists have been energized with discussion. At Alta, we have been following and contributing to this discussion and below are our current takeaways. These thoughts should not be taken as legal advice, however; each implementing agency should consult its own legal counsel before moving forward with any projects.
What we know:
1. RRFBs are very effective. Studies have shown that the two major components that make them effective are:
a. The irregular flashing pattern.
b. User actuation through push buttons (in most cases) so that drivers know the lights indicate the presence of people walking or bicycling crossing the roadway.
2. RRFBs are simple and relatively inexpensive – any viable alternative should have similar installation requirements.
3. Even if FHWA continues to prohibit their use, the need remains for a simple and effective device that meets the above criteria.
What if a project is in the implementation phase?
Several state DOTs have issued general guidance since the 21st. Generally, the discussions have focused on the following points:
1. If your project is built, the RRFBs can serve out their useful life.
2. If your project is under construction and RRFBs have been procured but not installed, they can be installed after December 21st.
3. If your project has been bid and a contractor is working, RRFBs can be ordered and installed.
4. If your project has not been bid and is still in design changes most likely should be made. Basically, this means finding an alternative “non-patented” design. This could take a number of different forms.
What are the alternatives to the RRFB?
There are many other treatments such as overhead lighting, raised crosswalks, curb extensions, median refuges and others which can positively influence crosswalk safety, this post focuses on alternatives to the RRFB itself – within a similar context.
1. In Roadway Warning Lights
While not suitable for all climates due to snow removal hazards which impact effectiveness and durability, In Roadway Warning Lights (IRWL) are a current tool allowed within the MUTCD. Chapter 4N of the MUTCD provides guidance on the use of IRWLs for pedestrian crossings, including a very important distinction on flash pattern.
a. IRWLs “shall initiate operation based on pedestrian actuation”
b. IRWLs provide flexible guidance on flash pattern, a potential issue with the other systems noted below. In 4N.03 -03 c, FHWA limits the flash rate to between 50 and 60 per minute, but allows for a continuous flash of varying intensity and time duration that is repeated to provide a flickering effect or pulse. This is a HUGE distinction from other flashing beacon guidance and we will return to it.
2. Traditional flashing beacon
MUTCD guidance on beacons is currently found in 4L.03:
a. One point of contention with the RRFB like irregular flash pattern is that the guidance contained in 4L.01 -03 states that “Beacons shall be flashed at a rate of not less than 50 or more than 60 times per minute. The illuminated period of each flash shall be a minimum of 1/2 and a maximum of 2/3 of the total cycle.” From this, it is unclear if a pulse of flashes as within the IRWLs could be interpreted as one ‘flash’ to meet the above guidance. The City of Los Angeles believes that it does and used a similar reasoning since 1999 in creating a rapid flashing beacon they called “Activated Pedestrian Warning Device”. The rapid flash and the push button actuation yielded safety benefits similar to RRFBs. LADOT defined each 3 quick flashes as a ‘pulse period’. The above guidance for IRWLs was also cited as basis for the pulse effect.
b. The 2009 MUTCD allows for pedestrian actuation, meaning push buttons are permissible.
c. Chapter 4L also allows warning beacons to be suspended over the roadway, where RRFBs are limited to side installations.
3. Perimeter LED warning signs
Another option is to return to the device that was gaining popularity just before RRFBs became approved, an embedded user actuated flashing amber LEDs in the warning sign itself. The MUTCD allows this to “improve conspicuity of the warning sign” among other uses. Unfortunately, language in the MUTCD still limits the flash pattern to more than 50 and less than 60 flashes per minute 2A.08. In the past perimeter LED warning signs have been paired with IRWLs and have used the same flashing pattern. The good news is that these installations can be slightly cheaper than RRFBs. However, once again, the interpretation of the flash pattern will influence the effectiveness of the device.
4. Solar hybrid beacons
A typical hybrid beacon looks a lot like a full traffic signal and costs almost as much. However, depending on context, it is possible to have the benefits of a hybrid beacon with a cost more similar to an RRFB installation. There is at least one manufacturer fabricating solar-powered hybrid beacons that are MUTCD compliant. The City of Tucson has installed solar-powered hybrid beacons with success. The MUTCD requires at least two beacon faces per approach. NACTO outlines challenges with hybrid beacons if using them for bicycle crossings. A shorter wig-wag phase should be considered.
What does all this mean?
Despite the initial shock of having such a well-regarded tool being removed from the toolbox, there are viable alternatives that can be installed in the short term in place of RRFBs. Try and create the same elements for success, an irregular flash pattern and push button actuation. Alta Planning + Design sees no reason to remove recommendations for beacons from projects or planning documents. It is likely that in the coming weeks or months a way will be found to make RRFBs permissible once again, or FHWA will provide further guidance to reinforce the alternatives mentioned above. FHWA has issued a memo defining many of the treatments noted above as well as others that was issued in late December. This memo has not circulated as widely as the memo rescinding IA-11.
Special thanks to the numerous transportation professionals who have actively participated in discussion through listserv, email and other means on this topic. This post incorporates many of the terrific points of discussion from this dialogue.
Please contact Joe Gilpin or Bryan Jones with any further questions. We look forward to hearing from you about your project.