Norouzi, AzadehDynamic Message Signs (DMS) are key components of Advanced Traveler Information Systems to manage transportation networks, reduce congestion and improve safety through providing motorists with real-time information regarding downstream traffic conditions. While DMSs are intended to improve efficiency and safety of road networks, little has been done to study the effect of the signs on driver safety and their localized safety impacts. This thesis employs ground truth data as the basis to investigate the issue in State of Maryland in a four-year period (2007-2010). The results show no significant difference between the accident pattern in the proximity of DMSs and the onward adjacent segments. On-and-off study is also conducted on DMS operation status (on/off). The results converge with the previous analysis suggesting that there is no meaningful relationship between occurrence of accidents and presence of DMSs. Besides, statistical analysis on DMS characteristics and accidents in impact areas are performed.ThesisCivil engineeringTransportation planningDatabase ManagementDynamic Message SignsGISRoad AccidentsSAS