The occasional traffic congestion has great randomness and derivatives,so it re-quires to control quickly to prevent the congestion spreading to advanced position and to dis-perse the congestion promptly.The area of congestion varies from the occurrence of traffic events to congestion dissipation.To dissipate traffic congestion,a fast dynamic definition method of the congestion region was put forward by traffic flow parameters and the propa-gation velocity of congestion.The traffic congestion region was divided into the blocking re-gion,transition region and normal region,and the traffic contr...