An automatic accident detection method based on traffic flow parameters will be accessed,through simulating the physical environment of urban tunnel with traffic simulation software VISSIM.

In accordance with the traffic flow parameter adjustment accumulative curve by Dganzo,a new method for defining traffic state change time is put forward.

Classification of the traffic flow state plays a very important role in the traffic control and guidance,there are difference of threshold of the traffic flow parameters in different freeway road section.

Video-based traffic flow parameters detection system has several apparent advantages such as easily intervened and lower costs.

Research on the Technology of Passive Acoustics Detection of Expressway Traffic Flow Characteristic Parameters;

Based on analysis of occupancy,analyze the three parameters of the share of the traffic flow,vehicles share and speed,and study the degree of sensitivity of traffic incident detected algorithm based on traffic parameters.

This paper proposes a detection method of traffic parameters based on the characteristics of video corner information,in which a detection region is divided into an initial one and a tracing one.

A designe scheme for detector of the highway traffic parameters is presented in this paper.