• Evaluating the Effects of Safety Vest Color on Visual Attention in Simulated Construction Work Zones

    NCDOT Research Project Number: 2020-49

 Executive Summary

  • Vehicular traffic in construction work zones presents many threats to worker safety on North Carolina Department of Transportation (NCDOT) projects. One method to ensure workers are seen by passing vehicles is for workers to don high-visibility apparel. Although research suggests that safety vests may increase the conspicuity of construction workers, no research specifically examines the effects of workers’ safety vest color on driver’s visual attention. The proposed work will address this current knowledge gap.

    The research activities for this proposed study will occur in two distinct phases. Phase 1 will serve as a preliminary study to test the effects of safety vest color on driver’s visual attention to worker vests in a preexisting computerized simulated construction work zone environment. For Phase 1 of this study, 81 participants will use a Trans-Sit driving simulator by Advanced Therapy Products while fitted with a Tobii

    Two Pro Glasses head mounted eye tracking system and will be asked to navigate a simulated construction work zone. Each participant will be randomly assigned a set of operational parameters including safety vest color and environmental condition via a Latin square design. Specifically, safety vest color parameters will be ANSI lime-yellow, ANSI fluorescent orange-red, and no vest. Environmental parameters will include day time, night time, and inclement weather. ANOVA analysis from eye tracking metrics will be used to determine if safety vest color and/or environmental conditions affect driver’s visual attention to workers. In Phase 1, the research team will also coordinate with NCDOT to obtain physical layout dimensions of an as-built construction work zone and will collect traffic density data of current NCDOT work zones using the iCone® radar-based vehicle monitoring system developed by iCone® Products, LLC. This data will be used to generate a reconstruction of an as-built construction work zone including realistic traffic density models in the simulator environment. During Phase 2, the research team will employ the reconstructed asbuilt work zone simulation for experimental testing in a realistic setting. In Phase 2 of this study, 81 different participants will be solicited. The experimental protocol for Phase 1 and Phase 2 is identical. However, Phase 2 will use the reconstructed as-built simulation environment to increase the ecological and external validity of the study.

    The primary contribution of this study lies in the exploration of how the presence of safety vests and their colors affect the ability of a driver to identify onsite workers. The results from this work will contribute to NCDOT’s goal of improving safety in work zones by providing standardized markings and colors that facilitate the visual identification of NCDOT employees. In doing so, the public will have more opportunity to avoid collisions with NCDOT employees operating in work zones.​


Dylan Hardison
Dylan Hardison
Jarvis Gray
Stephanie C. Bolyard
East Carolina University

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 Report Period

  • July 1, 2019 - June 30, 2021


  • In Progress


  • Traffic, Mobility, Safety and Roadway Design

 Sub Category

  • Traffic Management

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