April 27, 2018 

Nearly 6,000 pedestrians are estimated to have been killed in crashes with motor vehicles in 2017, a number that has been steadily increasing over time. It is the job of planners, policy makers, and engineers to protect all road users, including the most vulnerable ones.  One way to do this is through safety treatments targeted towards people who walk to decrease conflicts and crashes between pedestrians and vehicles. The federal government provides guidance regarding control devices to state and local agencies through the Manual of Uniform Traffic Devices (MUTCD) to create national standards and advance safety and efficiency on the national transportation network.

As pedestrian fatality rates increase, the Federal Highway Administration (FHWA) has added control devices to the MUTCD to further the goal of increasing pedestrian safety. However, a lack of robust safety studies regarding pedestrian safety treatments make it difficult for FHWA to approve additions to the manual, as the guidance should be based on evidence that the recommendation does indeed provide the intended positive safety effects.  The 2009 version of the manual includes the addition of pedestrian hybrid beacons (PHBs),also known as high-intensity activated walk (HAWK) signals,which have been shown to contribute to decreased pedestrian crash rates, as well as increased yielding to pedestrians by drivers. This clear correlation between the PHBs and increased safety made it a clearly relevant addition to the MUTCD.

In July 2008, FHWA issued interim approval for another type of signal for pedestrian safety called rectangular rapid flashing beacons (RRFBs) based on the implied safety value of increasing driver yielding to pedestrians. RRFBs are a treatment intended to improve safety for pedestrians crossing the vehicular right-of-way at a marked crosswalk without a traffic control signal.

RRFBs have been shown to increase driver yielding to pedestrians in marked crosswalks, but there are no strong studies suggested decreased crash rates as there are for PHBs.  The seminal study to date out of St. Petersburg, FL shows significant increases in driver yielding for both two- and four-beacon RRFB installation locations.

In December 2017 the interim approval for RRFBs was terminated due to the fact that the device had been patented and patented devices are not permitted in the MUTCD.  Agencies were not required to remove existing beacons, but installation of new ones, including if the installation had already been planned and the device had been purchased, was not permitted.  This left agencies in a bind where they had to re-plan, -design, and -budget pedestrian safety treatments where they had planned for an RRFB installation.  One benefit to RRFBs over PHBs is the lower cost of the device, which may have been the impetus for agencies to choose that treatment from the offset.

The private company later “expressly abandoned” the patents pertaining to RRFBs, and on March 20, the FHWA issued a new interim approval for the installation of the device, rationalized by the abandonment of the patent.

Now that agencies can again install RRFBs with the goal of promoting pedestrian safety, further research on the relationship between the devices and crash statistics should help inform FHWA as they develop the next edition of the MUTCD. It would also be beneficial for the guidance to express the benefits of treatments such as PHBs that may be slightly more expensive, but that have proven safety benefits for vulnerable road users.