Dispersion characteristics of time-headway on downstream section of signalized intersection

Dispersion characteristics of time-headway on downstream section of signalized intersection lay a foundation for urban road green wave control, traffic safety analysis, capacity research, etc. Applying roadside laser instruments, time-headway of 12 road cross sections on downstream section of a signalized intersection was investigated, and the time-headway values of 5 lanes were obtained. By means of regression analysis, the relationship between time-headway and the distance to upstream signalized intersection was studied, and the regression equations of the 5 lanes were established, namely, in peak period, there is a quadratic function relationship on 1 lane, there are all cubic functions on 2 to 5 lane, in off-peak period, there is a power function relationship on 1 lane, there are all cubic functions on 2 to 5 lane. Then, regression analysis method was introduced again to study the relationship between average time-headway of the same road cross section of all 5 lanes and the distance, and the cubic function models in peak and off-peak period were established, too. The results show that, after the vehicles leave the intersection, generally speaking, the time-headway are becoming bigger and bigger and the vehicles are gradually dispersed, but the dispersion processes are different. From 0 to 400 meters, the time-headway disperse sharply, while after 400 meters, it disperse slowly, finally after about 1000 meters, in off-peak period, the time-headway have shown stabilized trend, however, it still take some weaving characteristics in peak period.