A simulation study is developed to test variables of interest including: Roadway Type, Fog Level, DMS Presence, Beacon Presence, Traffic Volume, and DMS Message Provided. Using a factorial design, 24 scenarios are created by randomizing the variables listed using statistical software to be tested on 72 volunteer participants. Using a NADS MiniSim Driving Simulator, the participants driving behavior is recorded including speed and breaking behavior under an initial clear condition followed by a reduced visibility fog condition.
Post warning messages on DMS that describe how drivers should react to hazardous conditions rather than just notifying them of the hazard ahead. Presence of a DMS does not have a significant impact on the average change in driver speed until the fog condition becomes the most severe. Messages advising drivers on how to drive (e.g., "reduce speed") were found to be more effective than those solely warning of the presence of a hazard (e.g., "fog ahead").