Congestion and its side effects are increasingly considered as significant factors of lowering the quality of everyday life of the urban citizens and hindering the construction of green cities.The congestion and its studies around the world are briefly discussed,and based on the summary of the techniques of Internet of Things,a real world example of applying the RFID technique in urban transportation system is introduced,the Integrated Nanjing Intelligent Transportation System,including the system architecture,operational traffic condition monitoring and prediction,and the Youth Olympic Game oriented transportation application systems. <<