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December 14, 2022

MAPS Air Museum North Canton, Ohio

The high number of minor crashes at multi-lane roundabouts, especially at 2x2 roundabouts, might be the biggest issue related to roundabout implementation today. Some engineers and agencies choose other intersection options over 2x2 roundabouts to avoid the public relations nightmare that numerous crashes at 2x2 roundabouts can create. It is critical that we get to the bottom of this issue and do all we can to reduce the occurrence of crashes at multi-lane roundabouts.

This presentation will share the most important findings from the very detailed crash analysis of a very high-crash 2x2 multi-lane roundabout. It will also take a deep dive into specific crash patterns including the types and severity of crashes, traffic movements most often involved in common crashes, driver actions, and driver perceptions.

Roundabout design features and criteria at the existing roundabouts are explored and correlated to the crash data. Entering and circulating speed data will be discussed and compared to design values and related to crash patterns. 2 x 2 roundabout crash patterns observed and related factors will be explored in detail.

Proposed countermeasures will be shared, including photos/videos from already implemented countermeasures and preliminary crash reduction results. Steve has been involved with the study and/or design of over 200 roundabouts in six states. Including single-lane and multi-lane roundabouts. Steve has been a leader in roundabout analysis and design since 2003 and is currently a member of the TRB Roundabout Committee. He was an instructor for a full-day Roundabout Human Factors Workshop at the 2017 TRB Annual Meeting.

B&N Presenter:

Steve Thieken, PE, PTOE, AICP

Steve Thieken, PE, PTOE, AICP, Director, Columbus Transportation Division

Director, Columbus Transportation Division