Roundabout and Access Management

PI: Ruth Steiner, Ph.D., University of Florida
Co-PIs: Scott Washburn, Ph.D., University of Florida; Albert Gan, Ph.D., Florida International University

Funded by: Florida Department of Transportation

Transportation engineers and planners are increasingly interested in utilizing roundabouts to substitute for other intersection controls that contribute to both safety and traffic calming in the transportation system. While roundabouts are increasingly being used in a variety of contexts, existing research does not provide detailed guidance on how to incorporate access management into the design of roundabouts. Considering the importance of integrating access management considerations into roundabouts, this study attempts to answer the following main research question: “What access management aspects should be considered when designing and building roundabouts?”

To answer this question, this Florida Department of Transportation (FDOT) funded a research project has three primary components: a review of roundabout best practices and state guidance, operational and capacity analysis of a sampling of roundabouts, and a safety analysis of all roundabouts in the state of Florida. The review of roundabout research, state guidance and their application aims to understand how access management, capacity, and safety are addressed at roundabouts throughout the United States. Gaps in knowledge regarding the use of roundabouts are identified, particularly as they apply to safety, access, operations, and capacity. The safety analysis aims to find the relationship between crash occurrences  and the presence of driveways, median and other access management facilities. A smaller sample of roundabouts are identified to understand the operations and capacity of roundabouts in a variety of access management contexts in the state of Florida. Video recording, data collection, and observation are used to understand detailed contexts and access management aspects in the field.  The research will lead to the development of recommendations on desired access design features with respect to safety, design, and operations, inform an assessment of the primary software tools for assessing the capacity and operations of proposed roundabouts, and to develop recommendations for changes to the FDOT’s Access Management Tools, Median Handbook and Driveway Information Guide with respect to roundabouts.

Our research informs both federal and state guidance and suggests modifications to detailed guidance on access management considerations in roundabout guidebooks and handbooks.  Modifications to roundabout design guidelines and handbooks for access management will lead to safer, more effective, and ultimately, better performing roundabouts for all users of Florida’s transportation system and throughout the country.