Citation

Hagring O. Transp. Res. Circular 2000; (E-C018): 434-445.

Copyright

(Copyright © 2000, U.S. National Academy of Sciences Transportation Research Board)

DOI

unavailable

PMID

unavailable

Abstract

Roundabouts are normally considered as a series of T-intersections, each intersection regarded as being independent of the other intersections. Based on recent research on Swedish roundabouts a new capacity model for two-lane roundabouts was suggested. By use of this model it was found that changes of the Origin-Destination (OD) flows gave significant changes of the roundabout entry capacity. The model was compared with the OD model proposed by Akcelik. It was found that the effect of the OD flows on the roundabout entry capacity, predicted by the Akcelik model, can be divided into two parts, one depending on the degree of saturation and one depending on the OD flows. The effect of the OD flows will then be reduced from 55%, as stated by Akcelik, to 28%. Finally, explanations of the OD flow effects on a micro level are discussed.