Creating Effective Graphic Changeable Dynamic Message Sign (DMS) Messaging

Author/Presenter: Kondyli, Alexandra; Schrock, Steven D.; Mahajan, Kirti; Masud, Saumik Sakib Bin; Karki, Aayush Maan; Shrestha, Saurav; Tabatabaei, Mahgam
Abstract:

Successful transportation safety messages are only effective if travelers can comprehend the notices. However, one method of safety messaging, text-only messages, can be challenging for non-native English speakers and slow-reading populations, such as older adults. The addition of graphics can potentially improve message comprehension, but their effectiveness compared to text-only messaging campaigns is uncertain. This study evaluated the role of graphics, both with and without text, in enhancing comprehension and the effectiveness of dynamic message signs (DMS), with attention to demographic factors. Results showed that signs with graphics and text consistently outperformed graphics-only signs across all measures, including conspicuity, comprehension, ease of use, intention to comply, and memorability. The lowest-scoring signs lacked text, leading to poor interpretation accuracy and compliance. Statistical analyses confirmed that text significantly improved message effectiveness by reducing comprehension gaps between native and non-native English speakers. Age also influenced performance, with drivers older than 41 years old demonstrating higher effectiveness scores, likely due to driving experience. Logistic regression showed that age, literacy rate, and text presence positively predicted accurate sign interpretation. The findings indicate that graphics alone are insufficient for effective DMS communication, although pairing graphics with text enhances comprehension and compliance for all populations, especially for non-native speakers and young drivers. Awareness initiatives are recommended to improve familiarity with graphic signs