CEE’s Angelina Caggiano Publishes Paper on “Pedestrian Hybrid Beacons” in Journal of Safety Research

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Between 2011 and 2021, the number of pedestrian deaths in the United States increased 66 percent, to over 7,400 per year, and some three-quarters of pedestrian fatalities occur outside of intersections, such as at midblock crossings, where drivers are less likely to notice pedestrians. In response to this critical safety issue, Ph.D. candidate Angelina Caggiano of the UMass Amherst Civil and Environmental Engineering (CEE) Department was the lead author on her first paper published in a peer-reviewed academic journal. Her paper in the Journal of Safety Research describes trailblazing research on one solution to pedestrian fatalities known as “pedestrian hybrid beacons,” or PHBs. See An evaluation of driver comprehension of the Pedestrian Hybrid Beacon - ScienceDirect.

“A PHB is a special type of hybrid beacon used to warn and control traffic at an unsignalized location to assist pedestrians in crossing a street or highway at a marked crosswalk,” the Journal of Safety Research paper explains. The paper goes on to say that “PHBs are used as a method of increasing the safety of vulnerable road users by stopping vehicles at high-traffic and high-speed midblock crosswalks. This study was developed to evaluate both driver behavior and comprehension related to the use of PHBs in Massachusetts.” 

The Journal of Safety Research paper was titled “An evaluation of driver comprehension of the Pedestrian Hybrid Beacon.” Caggiano’s co-authors were: Jaji Pamarthi (Ph.D. candidate in Industrial Engineering); Tracy Zafian (research fellow at UMass Transportation Center); Michelle Deng (traffic safety engineer at the Massachusetts Department of Transportation, or MassDOT); Kirsten Johnson (GIS data specialist at MassDOT); Francis Tainter, Ph.D. (CEE research assistant professor); and Michael Knodler (professor in the CEE department and director of the UMass Transportation Center).

As Caggiano explains, “This paper, based on my master’s thesis, delves into driver understanding of PHB intervals—a critical topic for enhancing pedestrian safety and road-user awareness of midblock-crossing treatments.”

According to Caggiano’s Journal of Safety Research paper, “PHBs include four intervals of signal indications that notify drivers when a pedestrian or bicyclist seeks to cross the roadway. The PHB has a tri-signal head design that includes signal sections displaying two red indications above a single yellow indication.” 

As the paper makes clear, PHBs can be actuated either directly by pedestrians or cyclists pressing a button at the crosswalk indicating they would like to cross, or automatically (which is not common) through pedestrian or bicyclist detection.

The study utilized one online survey to create a PHB inventory and a second online survey to measure driver comprehension of PHBs in the commonwealth. The PHB inventory identified more than 40 PHBs currently installed within Massachusetts. The study also examined the reasons why drivers might be confused by PHBs and offered recommendations for education and outreach practices. 

“PHBs can increase pedestrian conspicuity on midblock crossings,” as the paper concludes. “Correct use of PHBs by drivers and pedestrians is crucial for facilitating safe crossings and traffic flow. However, many research efforts have not studied drivers’ understanding of PHB intervals. Communities with PHBs present should consider education and outreach prior to and during PHB implementation.” 

In addition to publishing the Journal of Safety Research paper, Caggiano recently presented the research described in her article during the Future of Transportation Summit at the U.S. Department of Transportation Headquarters in Washington, D.C. (February 2025)