Using video for data collection，and with the simulation value of two variables and the array of vehicle queue length，we establish the model of GM (1，N) and obtain the function relation between cumulative array of vehicle queue length and the other two variables.This formula can indirectly explain the relationship between vehicle queue length and the cross-sectional actual capacity and the sections of upstream traffic.

%U https://zkxb.jsu.edu.cn/EN/10.3969/j.cnki.jdxb.2016.05.004