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Fresno State Transportation Institute

Moving Towards Roundabouts in California

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Project Overview:

Roundabouts are designed to improve traffic safety and keep vehicles moving efficiently by reducing conflict points and lowering speeds. In California, building roundabouts has been met with pushback from the public and nearby businesses.

This research examined roundabouts in California to understand their safety performance and how they are perceived by the public and business community. The study used geocoded crash data from the Statewide Integrated Traffic Records System (SWITRS) to compare crash trends before and after construction, including by crash severity, road user type such as pedestrians, cyclists, motorcyclists, and DUI drivers, as well as single- and multi-party crash counts. The team also gathered sentiment from business owners and managers located near selected roundabouts through in-person interviews, and from the general public through a statewide stratified online survey using Qualtrics.

The information from these efforts was used to develop outreach and messaging strategies that can help transportation agencies, planners, and local governments address misconceptions and improve acceptance of roundabout projects in California.

Full Report (Coming Soon) Infographic (PDF Coming Soon)

Project Presentation

Presentation Webinar Hosted by Caltrans:

This presentation showcases the final results of the project, highlighting key findings on roundabout safety and public perception across California. The webinar included a 40-minute presentation followed by over an hour of Q&A, with sustained participation throughout. The event reached over 2× the typical viewership and 6× the average engagement, demonstrating public interest in roundabout implementation.
Presentation Slides Short Video Summary

 

Our Summary Poster was showcased in the International Conference on Transportation and Development (ITCD 2025), additonallhy the 45th Annual Central California Research Symposium. See poster below

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Collective Collaborative Showcase

Fresno State Transportation Institute Project Team:
Principal Investigators:
  • Alexis Perez, Undergraduate Civil Engineer at Lyles College of Engineering
  • Aly Tawfik, Director of the Fresno State Transportation Institute & Professor of Transportation and Systems Engineering in the Lyles College of Engineering
  • Samer Sarofim, Associate Professor of Mechanical Engineering in the Lyles College of Engineering
Project Partners Caltrans:
  • John Liu, Caltrans Deputy District 6 Director, Maintenance and Operations
  • Edwin Yeung, Caltrans Transportation Engineer

photo of members

Image of ThankYou to Peer Review Panel

This research was funded by the California Department of Transportation (Caltrans) under Task Number 3973

 

For more information, contact:

Dr. Aly Tawfik
Professor of Civil Engineering in the Lyles College of Engineering
tawfik@csufresno.edu
559.278.2500