To develop an approach to evaluate the capacity reliability of road network based on ice and snowfall conditions,the capacity reliability was studied on the basis of travel time reliability and capacity of links.The concept of network capacity reliability was proposed.Through the introduction of free travel time and capacity correction functions for Bureau of Public Roads (BPR) model,an Ice and Snowfall Based-Bureau of Public Roads (ISB-BPR) function was proposed.Then the bi-level programming model of road network capacity reliability was developed.The travel time reliability and link capacity as restrictions were proposed in the upper programming model.To follow the characteristics of route choice under ice and snowfall conditions,the elastic demand user equilibrium (EDUE) was set up in the lower programming model.An assessment methodology integrating sensitivity analysis of EDUE and Monte Carlo simulation was proposed to evaluate the capacity reliability.A numerical case was also given to demonstrate the practicality of the given model.The results show that the ice and snowfall intensity,traffic supply and demand all have great influence on the capacity reliability.The methodology is useful and applicable.It may provide a basis for network planning,design and maintenance.