Field Evaluation of Methods for Enhancing Sign Conspicuity

Abstract

The 2009 Manual on Uniform Traffic Control Devices (MUTCD) outlines various strategies to
enhance the conspicuity of traffic signs, defined as a traffic sign’s ability to stand out and attract
attention. Improving sign conspicuity is believed to directly and indirectly impact safety by
promoting compliance, reducing speeds, and decreasing accidents. However, despite these
enhancements, there is a lack of comprehensive research on their actual effectiveness on driver
behavior. This study aims to fill that gap by evaluating the effectiveness of these conspicuity
treatments, focusing on methods currently endorsed by the MUTCD rather than exploring novel
treatments.
To conduct this evaluation, the research team reviewed existing literature and practices,
consulting with members of the Traffic Control Devices Pooled Fund Study (TCD PFS) to
identify which MUTCD treatments were being effectively utilized across states. Given that
conspicuity, especially retroreflectivity, cannot be effectively replicated in laboratory settings, the
researchers employed field experiments to gather data. They utilized a two-part approach,
combining observational field data and eye-tracking studies, to assess how these conspicuity
treatments influence driver behavior. This methodology allowed for a nuanced understanding of
whether these enhancements lead to increased attention to signs and subsequent changes in
driving behavior.