RELATIONSHIP BETWEEN UNINTERRUPTED AND INTERRUPTED SPEED AT ISOLATED SIGNALIZED INTERSECTION

Abstract

This paper attempts to define the relationship between the uninterrupted and interrupted speed at the under-saturated and saturated isolated signalized intersection using the method of characteristics. Due to the nature of interrupted facility of urban road, the effect of detector location is also considered in the model. The model is tested with several sets of simulated traffic data including the under-saturated and saturated conditions, and under the linear and nonlinear density-speed relationship. In some cases, the estimated speed value is not in the feasible region so decreases the estimation accuracy. The introduction of the free flow speed as the upper limit of the estimation leads to more accurate estimate. The results from the proposed method are compared with the results obtained from the trajectory-based method proposed in the earlier work. It is found that the method of characteristics outperforms the trajectory-based method in all cases of traffic data.