Guidelines for Three-Lane Road Design and Operation

Wednesday, March 9, 2022, 10:00–11:30 am

About the Webinar

Road diets, which convert four-lane undivided highways to three-lane cross sections, are an innovative solution to address mobility and safety concerns under budgetary constraints. Past research has primarily focused on evaluating the safety of road diets, but there has been less research on the operational effects of such redesigns. This lack of guidance can lead agencies to avoid conversions on roadways with AADTs greater than 15,000 vehicles per day, even though anecdotal evidence suggests successful operation of three-lane roads with AADTs upwards to 25,000.

This presentation highlighted a U of M research project that aims to review existing guidance on three-lane road conversions and identify conditions where three-lane conversions might be feasible for roads with AADTs greater than 15,000.

The webinar was held in a conjunction with a CTS Transportation Safety and Traffic Flow Research Council meeting.

Webinar Materials


Jordan Kocak
Jordan Kocak
Gary Davis
Gary Davis

Gary Davis is a professor in the Department of Civil, Environmental, and Geo- Engineering at the University of Minnesota. His research interests include causal inference and impact assessment in traffic safety; application of accident investigation and reconstruction methods to traffic engineering questions; the use of Bayesian statistical methods in traffic and transportation engineering; and the application of optimization methods to problems in traffic engineering and transportation planning.

Jordan Kocak, AICP, is a transportation planner and the pedestrian and bicycle coordinator for Hennepin County, Minnesota. He works on multimodal and safety focused restriping and capital projects, many of which include analysis and design of four- to three-lane conversions. He holds a Bachelor of Arts in urban studies from the University of Minnesota and a Master of City and Regional Planning from the Bloustein School at Rutgers, The State University of New Jersey.