Travel Time Reliability of Urban Road Network Based on Generalized Travel Cost

To describe travelers' route choice characteristics and accurately evaluate travel time reliability on road network,the concept of generalized travel cost was introduced.It was defined as the weighted sum of the mean travel time and the mean square deviation,in which the weighted coefficients reflect the different travelers' attitude towards uncertainty.The travel time reliability was defined on the level of link,and the stochastic user equilibrium (SUE) assignment model was formulated on the assumption of minimization of generalized travel cost in choosing the path.The travel time reliability model based on generalized travel cost was developed.Based on the characteristics of the models,the algorithm that integrated Monte Carlo simulation and traffic planning model was put forward,and a numerical case was also provided to demonstrate the practicality of the proposed model.The results show that(1) the travelers' attitude towards uncertainty has an obvious impact on the travel time reliability;(2) the conservative attitude can improve the travel time reliability of road network in some degree.Moreover,the proposed model could well reflect the route choice in reality and make the analysis of travel time reliability more accurate.