The identification of the oversaturted traffic conditions at the signal control intersection helps to control traffic congestion.In the investigation,based on the detection data of inductive loop detectors,the traffic wave theory is utilized to identify the oversaturated traffic condition from two aspects,namely,the retention queue length at the end of the green light at an intersection and the overflow of the downstream intersection.Aiming at the first aspect,the queuing dissipated coefficient is defined to identify the oversaturated traffic condition at the intersection.Aiming at the second aspect,the overflow retardation coefficient is defined to reveal the oversaturated overflow phenome-non.Case study results show that oversaturated traffic condition can be accurately and effectively identified by cal-culating the queue dissipation coefficient and the overflow retardation coefficient based on the loop detection data.