Alternative Information Signs: Evaluation of Driver Comprehension and Visual Attention

Abstract

The effectiveness of a traffic sign is collectively influenced by the sign’s understandability, legibility distance, glance legibility, and learnability; however, understandability has been repeatedly identified as one of the most important effectiveness measures. This study contributes to best practices for evaluating traffic sign understandability by demonstrating and comparing a variety of online survey questions and immersive driving simulation tasks. These techniques were applied to assess the understandability of five alternative tourist information (TI) signs in Oregon. Several TI sign alternatives were first tested in an online survey with 142 participants, followed by more authentic testing of 42 participants in the Oregon State University Driving Simulator. Sign INFO was correctly understood by 95.7% of the driving simulator subjects. Similar results were obtained for the other testing modalities. Notably, the understandability of TI sign alternatives, including versions with (75.4%) and without (72.8%) a circular border, did not score as high despite their prevalent usage in other contexts. However, the Sign i comprehension rates increased dramatically over those from an earlier study, indicating that periodic review of sign comprehension rates may be needed to reflect changes in understandability with time.