Florida I-75 DDI

Innovative HDR Diverging Diamond Interchange Project Honored with Six Awards

The redesigned I-75 and University Parkway interchange in Sarasota, Florida, is the largest diverging diamond interchange in the United States and the first in Florida. HDR was the prime consultant responsible for reconstructing and designing the interchange. The project recently received the following awards:

  • America’s Transportation Awards, Southeastern region winner in Best Use of Technology & Innovation, medium category. The three highest scoring projects from each region will compete for Grand Prize and People’s Choice awards that will be announced September 23 at the American Association of State Highway and Transportation Officials’ annual meeting.
  • Florida Transportation Builders Association, Best in Construction for Interchange.
  • American Council of Engineering Companies of Florida, Grand Award in Transportation, and Outstanding Project Award, Major Project. The project also received a National Recognition Award from ACEC.
  • Seventh place in the Roads & Bridges magazine Top 10 Roads Projects of 2018.

About the Project

By creating a continuous flow of traffic instead of using traditional traffic signal crossings, the new design has relieved one of the largest traffic bottlenecks in southwest Florida. More than 60,000 vehicles per day traveled this congested intersection and the number was anticipated to grow to more than 80,000 by construction completion. The new design reduces intersection delay by about 50 percent.

In addition to providing a smoother traffic flow, the DDI design eliminated 12 conflict points and improved sight distance for drivers. These changes are expected to reduce the overall crash rate by 30 percent, and angle crashes by 70 percent. The design also offers safe pedestrian and bike accommodations including bike lanes, signal-protected crosswalks and a 14-foot-wide walkway.

Since DDIs had not previously been used in Florida, a comprehensive public involvement plan including meetings, renderings and 3D videos showing both aerial views and views from the driver’s perspective helped garner public support. The project also included reconstruction of University Parkway, two bridge widenings and two bridge replacements. It was completed on schedule and opened to traffic in late May 2017.

HDR has analyzed or designed more than 85 DDI projects throughout the United States and Canada.

About HDR's Transportation Experience

Our award-winning transportation practice is known for solving our clients' most complex mobility challenges across all modes of travel. We are helping with multibillion-dollar programs ranging from managing the Council Bluffs, Iowa Interstate rehabilitation program and the San Diego Mid-Coast Corridor Transit project to designing the I-4 Ultimate P3 project in Florida and the new Governor Mario M. Cuomo Bridge in New York. In addition to planning and engineering, our experts help clients advance projects and programs across the infrastructure life cycle with strategic funding, economic analysis, public engagement, real estate services, program/project controls, risk management and operations and maintenance.

About HDR

For more than a century, HDR has partnered with clients to shape communities and push the boundaries of what’s possible. Our expertise spans nearly 10,000 employees, in more than 200 locations around the world — and counting. Our engineering, architecture, environmental and construction services bring an impressive breadth of knowledge to every project. Our optimistic approach to finding innovative solutions defined our past and drives our future.