Intersection traffic flow analysis and analysis of algorithms, design of algorithms, this paper, the vehicles unified identification as a standard car equivalent steps of the algorithm based on the decision-making on the flow of traffic junctions, the algorithm is applicable not only to single-coil detector or single magnetic detector such as a single detector, but also applies to dual-loop detectors. The detection process is simple and can achieve very high accuracy rate, and through case studies, to verify the effectiveness and accuracy of change algorithm.