Abstract: To study the condition of different reforming plans for separating trucks from passenger vehicles and provide guidance for reforming, an index system was proposed in this paper including the indexes of delay, times of changing lanes, coefficient of speed variance etc. The principle component analysis was used to simplify this index system and a selection and evaluation method for separating trucks and passenger vehicles was provided. Then, the effectiveness of this method was testified by applying the theory of serial number summation. The result shows that this method is superior to other current methods in the literature.