Abstract
This study is to analyze speed variation at merging section of successive entrance ramp and to suggest design criterion of ramp spacing at successive entrance ramp in urban area. The major findings are as follows ; (1) The relationship between the speed at merging section of successive entrance ramp and the distance from the merging point represents concave curve. (2) The 85 percentile speed(S) at outside lane (lane 1) is modeled S = 49.5 + 355.7(D/Q) - 0.94(D2/Q) + 6.78(D/AL2) where, D = Distance from merging point(m), Q = Lane 1 volume(vph) AL2 = Acceleration length at second entrance ramp(m) (3) The more traffic volume and the shorter acceleration length of the second entrance ramp, longer ramp terminal spacing is needed.
