Comparison of Driver Yielding for Three Rapid-flashing Patterns Used with Pedestrian Crossing Signs

Fitzpatrick, Kay; Avelar, Raul Eduardo; Robertson, James; Miles, Jeff · 2015 · ROSA P / United States. Federal Highway Administration

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Summary

This study addresses the variability in driver yielding rates observed with Rectangular Rapid-Flashing Beacons (RRFBs) at pedestrian crosswalks. While RRFBs generally improve yielding compared to uncontrolled crossings, previous studies reported rates ranging from 22% to 98%, suggesting that device characteristics, such as flash patterns, may influence effectiveness. The research was motivated by the need to standardize RRFB specifications for inclusion in the Manual on Uniform Traffic Control Devices (MUTCD). Specifically, the study investigated whether alternative flash patterns, particularly those with increased dark periods to aid pedestrian detection, would maintain or improve driver yielding compliance compared to the originally approved "2-5" pattern. The research team conducted an open-road field study at eight sites in College Station and Garland, Texas, during February and March 2014. To ensure consistency, temporary light bars were installed in front of existing RRFBs, allowing researchers to control brightness and flash patterns. Three patterns were tested: the baseline "2-5" pattern, a "Blocks" pattern featuring long and short flashes, and a "WW+S" pattern combining wigwag and simultaneous flashes. The latter two were selected based on expert workshop recommendations to include longer dark periods. Data collection utilized a staged pedestrian protocol, where researchers acted as pedestrians crossing the road while observers recorded driver yielding behavior. A minimum of 40 crossings per condition were recorded per site, totaling 120 crossings per site, under daylight conditions with moderate traffic. Statistical analysis using logistic regression on individual crossing data revealed no significant differences in driver yielding rates among the three flash patterns. The average yielding rates were 80% for the Blocks pattern, 80% for the WW+S pattern, and 78% for the 2-5 pattern. Although previous closed-course studies indicated that patterns with longer dark periods help drivers identify pedestrian direction more quickly, this field study confirmed that such patterns do not compromise driver yielding compliance during daytime conditions. The findings have direct implications for traffic control device standards. Because the WW+S pattern offers greater dark time—improving sign readability and pedestrian visibility, especially at night—and lower total on-time for energy efficiency, the Federal Highway Administration (FHWA) issued an official interpretation favoring its use. Consequently, the FHWA permitted agencies to use either the 2-5 or the WW+S pattern, with a preference for the latter. This study supports the adoption of flash patterns with increased dark periods as they provide operational benefits without reducing driver yielding effectiveness.

Key finding

There were no statistically significant differences in driver yielding rates between the 2-5, Blocks, and WW+S flash patterns, with yielding averages of 78, 80, and 80 percent respectively.

Methodology

on_road

Sample size: 8

Provenance

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

Topics

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• vru conspicuity
• rail grade crossings
• vru facing ehmi
• driver vru interaction