The Potential Effects of Composition and Structure of Dynamic Message Sign Messages on Driver Beha..
By: Samira Ahangari
In this study the research team reviewed the literature and best practices and then completed a comprehensive comparison of content, type, length of the message, and standards of dynamic message signs (DMSs) and their effect on driver behavior. The research team also investigated the potential effect(s) of various formats and content of DMS displays on driver’s route choice and compliance behavior using a driving simulator and survey questionnaires. The diversion rate, a measure of the ability of the message(s) displayed to divert traffic in a given direction, of different message types was also investigated. A 155-square-mile (400-km2) road network in Maryland was simulated, and different scenarios were considered. A total of 390 simulation runs were conducted by 65 participants from diverse socioeconomic backgrounds. Single-phase messages were always preferable to two-phase messages, as motorists could comprehend single-phase messages faster. Two three units of information on a DMS led to an increase in overall speed while six-seven units of information led to a decrease in overall speed when approaching and passing a DMS. A route diversion analysis, a route choice analysis and a compliance analysis identified the different DMS that have a high likelihood of influencing these behaviors. Lane closure and delay information with advisory messages were found to be the most influential DMS regarding diversion. Color-coded DMS and avoid route advice were the top contributors to route choice decisions and DMS compliance. The pre/post simulation surveys and driving simulation results confirm the findings of the effectiveness of the color blind friendly, color-coded DMS over the others. Interestingly, people who stated that they would choose their navigation system over a conflicting DMS message were the ones who complied with most of the advisory DMS in the absence of a navigation system in this study.