This paper presents an assessment of the roundabout capacity model given in the new Highway Capacity Manual 2010 (HCM 2010) with a focus in its use in the SIDRA INTERSECTION software. The model can be viewed as a non-linear empirical (regression) model with a theoretical basis in gap-acceptance methodology. The general importance of some fundamental aspects of the model is discussed. Model extensions provided by SIDRA INTERSECTION are discussed. Using a multilane roundabout example given in HCM 2010, capacity and the resulting degree of saturation (v/c ratio), delay, level of service and queue length estimates from the HCM 2010 model are compared with those from the SIDRA Standard capacity model for roundabouts. Discussions are presented in relation to the finding of lower capacity of roundabouts in the USA compared with Australian and UK roundabouts and the issue of possible increases in roundabout capacities in the USA over time due to changes in driver behaviour.
AKÇELIK, R. (2011). An assessment of the Highway Capacity Manual 2010 roundabout capacity model. Paper presented at the International Roundabout Conference, Transportation Research Board, Carmel, Indiana, USA, May 2011.