Arlington County Finds the Best Spots for Rectangular Rapid Flashing Beacons

NHTSA · 2020 · ROSA P / United States. Federal Highway Administration

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Summary

This case study examines Arlington County, Virginia’s systematic approach to implementing Rectangular Rapid-Flashing Beacons (RRFBs) to enhance pedestrian safety at uncontrolled crossings. Motivated by high pedestrian activity resulting from the county’s proximity to the Washington, D.C. metropolitan area, Arlington County sought to maximize the safety benefits of RRFBs—a pedestrian-actuated device consisting of flashing yellow LED arrays—through data-driven site selection. The study focuses on the evaluation of the first 10 RRFB installations completed by the end of 2017 and informs the planning for an additional 20 installations targeted for completion by the end of 2020. The Arlington County Department of Environmental Services’ Transportation Engineering and Operations conducted a comprehensive evaluation of the initial 10 sites, which were distributed across various settings within the county. The research design involved collecting specific operational data to answer key questions regarding pedestrian and driver behavior. Metrics recorded included the frequency of pedestrian actuation, pedestrian volumes and characteristics, driver yielding rates, and changes in vehicle speeds when the RRFBs were flashing. Additionally, the team recorded static site characteristics, such as the number of lanes and posted speed limits, to contextualize the behavioral data. The evaluation yielded significant quantitative results regarding driver behavior. Following RRFB installation, driver speeds decreased by 15 percent across the study locations. Driver yielding behavior improved substantially, with an overall increase of 110 percent in yielding, resulting in a post-implementation yielding rate of 70 percent. Pedestrian volumes also increased at these sites. Crucially, the county modeled the average driver yielding rate as a function of the 85th-percentile speed (measured when RRFBs were not flashing). The analysis revealed a logistic relationship where yielding rates decrease as speed increases. Specifically, within the 30 to 35 mph range, every 1-mph reduction in speed corresponded to an 11-percent increase in the average driver yielding rate. The model indicated that yielding rates drop from 75 percent at 30 mph to 50 percent at 34 mph, and further to 25 percent at 37.5 mph. These findings directly influenced Arlington County’s best practices and siting guidelines. The county established criteria to screen out high-speed roads (40 mph or above) from potential RRFB locations, prioritizing sites with the highest potential benefit. The updated guidelines now allow practitioners to determine appropriate treatments based on factors including average daily traffic, pedestrian activity, posted or 85th-percentile speed, lane configuration, and median presence. For locations with higher speeds, the county recommends combining RRFBs with speed mitigation measures, such as speed feedback signs or enforcement, to augment safety effects. This data-driven framework ensures that future RRFB implementations are strategically placed to optimize pedestrian safety and driver compliance.

Key finding

After RRFB installation across 10 sites, driver speeds dropped 15 percent and driver yielding increased 110 percent, reaching a 70 percent yielding rate.

Methodology

field_study

Provenance

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Summary generated by qwen3.6-27b-prismaquant on 2026-06-10; verification: verified.

Topics

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• perceptual countermeasures