Weather conditions have certain impacts on roadway traffic operations, especially traffic safety. Bridges differ from most surface streets and highways in terms of their physical properties and operational characteristics. This research assess the driving risk under different weather conditions through focus group firstly, then it develops a multi-ordered discrete choice model that is used to analyze and evaluate driving risks under both single and dual weather conditions. The data is derived from an extensive questionnaire survey in Shanghai. And the questionnaire includes those factors related to roadway, drivers, vehicles, and traffic that may have significant impacts on traffic safety under severe weather conditions. Considering the actual situation these variables except driver's gender are selected as independent variables of risk evaluation. As a result, different risk levels and corresponding probability are calculated, which are very important to optimize emergency resource allocation and make reasonable emergency measures. Moreover, in order to reduce severe bridge-related crashes, the research develops an ordered probit model to analyze those factors contributing to bridge-related crash severity and to predict probabilities of different severity levels under rainy conditions.