Research On Design Index And Method Of Breakaway Roadside Sign

China’s vehicle population has a trend of geometric growth, as a result, the safety issue of traffic is severe, and the whole society pays much attention on it. Roadside traffic accidents make up a large proportion among all traffic accidents. When vehicles crash roadside signs, the accidents are always severe and cause harm to people’s safety and property badly. Study on breakaway roadside signs can reduce the severity of traffic accidents, protect crashed vehicles and people inside. The study can provide theoretical support and decision basis for management department of road transportation and has much theoretical and practical value.Domestic and international researches in this area are summarized and analyzed in the study. The study analyzes the force load of breakaway roadside signs, draws lessons from American standard and gets out design index that suits our country well with facts in our country well considered.Having the guide of design thought, the study classifies the connections between sign base and pole into three kinds on the base of material properties, which are later evaluated by using analytic hierarchy process. Researches on breakaway pole and hinge joint are also made.Location criteria of breakaway roadside sign is also studied, including influencing factors, application conditions, location position and direction.Finally, by using the preceding research results and finite-element numerical method analytical tool ANSYS, the paper builds models for normal signs and two designed breakaway roadside sign structures. The study calculates the combination of loads, proves this design theory is exactitude by simulating and comparing the models.