Free Web Tool · HCM 2010

Roundabout Capacity

Single- and two-lane roundabout entry capacity per HCM 2010 Eq. 21-1 (c = A·e^(−B·v_c)) with V/C ratio and approximate LOS.

Input

Results

A coefficient
B coefficient
Capacity c (veh/hr)
PCE-adjusted demand v_e,pce
V/C ratio
Approx. LOS
Method

HCM 2010 Eq. 21-1: c = A · exp(−B · v_c). For 1-lane entry: A=1130, B=0.001 (per 1L circ), or A=1130, B=0.0007 (2L circ). For 2-lane entry to 2-lane: c_left=1130·exp(−0.00075·v_c), c_right=1130·exp(−0.00084·v_c). Adjust v_e by PCE for heavy vehicles: v_e,pce = v_e · (1 + p_HV·(PCE−1)).