Factor analysis based evaluation on level of service for basic segments in urban expressway

Basic segment is one of the most essential parts in urban expressway system. The level of service (LOS) for basic segment affects the efficiency of expressway and moreover urban road network. This paper presents an evaluation method on LOS for basic segments in urban expressway based on factor analysis (FA). Firstly, the characteristics of basic segments are analyzed. Then the factors of LOS for basic segments are introduced from the aspects of geometrical characteristics, vehicle characteristics and traffic characteristics. Secondly, the model expression of FA, the adaptability of FA based evaluation and the calculating procedure of LOS are given. Lastly, the application of this method is illustrated by taking twenty two basic segments for urban expressway in several cities such as Tianjin. The results indicate that FA based method is effective in evaluating the LOS for basic segments in urban expressway. Furthermore, the effect weights of different factors can also be detected.