Flower roundabouts and double-lane roundabouts: a comparative performance analysis

摘要

In the paper, a choice criterion between fl ower roundabouts and double-lane roundabouts is\udproposed, focusing on operational benefi ts that can derive from one scheme over the other, and\udoutlining a general framework for benefi t-cost analysis. In order to assess operational benefi ts of\udinnovative roundabouts over modern roundabouts, a comparative analysis was made. Capacity was\udestimated using gap-acceptance models. In detail, assuming the dichotomic shifted negative exponential\uddistribution to model headways in circulating streams, the Hagring formula was adjusted to\udobtain entry capacity estimations at roundabout approaches where entering vehicles face one or two\udconfl icting fl ows. Based on the control delay, the suitability domains and indifference areas were\udconstructed. Thus, a sensitivity analysis to changes in traffi c demand for operational benefi ts of\udfl ower roundabouts over double-lane roundabouts was carried out and discussed. At last, evidence\udfor new installations and conversion of existing roundabouts can be found