SIDRA Multimodal Capacity and Performance Analysis for Roundabouts

Aerial photograph of road


This TRB Annual Meeting presentation is a contribution to a session on areas where multimodal capacity and performance models for roundabouts can be improved in future versions of the Highway Capacity Manual (HCM). The presentation provides information about existing features of the SIDRA INTERSECTION software for this purpose. It also suggests the areas where there are current gaps in the basic aspects of HCM roundabout capacity and performance models. This PDF copy of the PowerPoint presentation includes the following sections:

  • SIDRA Capacity and Performance Output by Movement Class, Pedestrians and Persons (includes an example with a roundabout bus bypass lane).
  • Multimodal Gap Acceptance Capacity Model in SIDRA (applies to all gap acceptance processes at roundabouts, unsignalized pedestrian crossings as well as sign-controlled and signalized intersections).
  • Features of the SIDRA roundabout analysis method relevant to "gaps in HCM" (includes the HCM Edition 6 Extended Roundabout Capacity Model).
  • SIDRA Site and Network Templates for Roundabouts (includes reference to the SIDRA Dutch Bicycle Roundabout template).
  • A detailed study of the HCM roundabout capacity model (includes an assessment of the HCM model with the suggested addition of a “Basic SIDRA Geometry Method”).
  • Movement and Place approach in Australia.


AKÇELIK, R. (2024). SIDRA Multimodal Capacity and Performance Analysis for Roundabouts. Presentation at TRB 103rd Annual Meeting, Session 3068: Multimodal Operations and Capacity of Roundabouts in the US and Beyond, Washington D.C., USA, January 2024.

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