COMPARISON OF SATURATION FLOW RATES AT SIGNALIZED INTERSECTIONS

A overview is presented of studies conducted to estimate saturation flows at signalized intersections. A summary of the estimates of the per-lane straight-through saturation flows at signalized intersections reported in the literature is tabulated. It shows that, with a few exceptions, the estimates of straight-through saturation flow developed over the years have been in the range of 1600-1800 vphgl, with the more recent estimates favoring the high end of the range. The study findings are significant in terms of the recent emergence of critical movement analysis of techniques as the basis for determining signalized intersection capacity and level of service. It is noted that the choice of saturation flow values probably has a greater effect on relative prediction errors than any minor differences that might exist in current critical movement formulations.