HCM 6 Extended Roundabout Capacity Model in SIDRA INTERSECTION

Abstract

This conference presentation describes an extended version of the HCM Edition 6 Roundabout Capacity Model.  As roundabouts become more widely adopted, a greater variety of multi-lane configurations and more frequent use of slip/bypass lanes are considered in design proposals. The HCM Edition 6 Extended Roundabout Capacity Model application in SIDRA INTERSECTION version 9.1 was developed using the results of roundabout surveys carried out for Wisconsin DOT in the USA. It provides the ability to specify more detailed capacity model parameter values that distinguish different lane configurations. In particular, it allows the calibration of slip/bypass lane capacities independently of entry lane capacities and also adds parameters for three-lane entries. Application of survey data collected for Wisconsin DOT to the Extended Model is discussed.