Roundabouts are a performance-based intersection and their operations and safety are predicated on adherence to design principles for safety. Many multi-lane roundabouts are having excessive PDO (property damage only) or minor crashes, which is creating challenges for future implementation of roundabouts in these communities.
This presentation will discuss how design safety principles affect how drivers receive and process information. For optimal safety and operations the roundabout design must simplify decision-making and provide clear, concise information as to the correct way to drive the roundabout.
We will present two case studies:
- The design review of an existing poorly performing “urban, multi-lane” roundabout
- A roundabout design optimization/peer review for a “rural, high-speed” application
We will discuss the essential design components for optimal roundabout safety and operations, including:
- Operations/Geometrics: Avoiding Over-Design
- Safety Design Principles
- Improving Driver Messaging and Information Processing
Mark T. Johnson, PE
Mark Johnson is Principal Engineer for MTJ Roundabout Engineering. Mark founded MTJ in 2005, after 12 years of public- and private-sector transportation engineering positions, including 4 years for the City of Loveland, Colorado, and 4 years at the Wisconsin DOT where he was a key contributor to WisDOT’s roundabout program.
Mark has published papers on roundabout design and application issues and is a co-author of the 2010 FHWA Roundabout Guide (NCHRP 672). Mark is an authorized FHWA Peer-to-Peer Roundabout Reviewer, Vice Chair of the ITE Roundabout Committee, and an active member of the TRB Roundabout Committee.