Hitherto,researches on intersection delay estimation have revealed that deviations mainly originate from the exactitude of the position that separates the intersection from segments.By analyzing the delay process of the traffic flow in the intersection,the floating car method and the deceleration point method are proposed by utilizing data near the intersection.The analysis of real-time data from the City of Nanjing demonstrated that the proposed methods can effectively reflect the time-dependent law of traffic flow changes at the intersection and they have a high accuracy of dynamically circumscribing the area of the intersection.Compared with the intersection's static subsection,the proposed methods are more flexible and have certain advantages for estimating intersection delay and traffic conditions as well as calculating travel time.