FDOT I-95/45th Street Interchange PD&E Study

Project Summary

Interstate 95 is the main interstate highway on the East Coast, stretching 1,920 miles from Miami to the Canada-U.S. border. 45th Street connects West Palm Beach, Florida, to the town of Mangonia Park. The 18th busiest container port in the U.S., the Port of Palm Beach, is 4 miles from the interchange. Consequently, there is a lot of traffic on I-95’s 10 divided lanes and the six divided lanes on 45th Street. The interchange carries more than 41,000 heavy freight trucks daily. The site has frequent traffic jams, congestion and accidents.

Hanson prepared an innovative project development and environment (PD&E) study for I-95 and 45th Street that proposed the first diverging diamond interchange (DDI) for the Florida Department of Transportation’s (FDOT) five-county District 4. When implemented, the DDI — which causes traffic to briefly cross over to the opposite side of the road — will solve traffic problems that a conventional diamond interchange would not.

In March 2016, the project team began studying how to alleviate existing and future traffic congestion, identifying the short- and long-term needs of I-95 and improving safety at the interchange. Traffic backing up to the mainline of I-95 needs to be prevented in the short-term; long-term, the interchange needs to accommodate future traffic demand.

The study included a comprehensive public involvement program, which encompassed kickoff meetings, alternatives workshops, hearings, a project website and coordination with local municipalities.

The DDI, which will be navigable via specially designed traffic signals, will reduce the number of conflict points to 14, compared to 26 for a conventional diamond interchange.

Other benefits will include improved safety at the interchange, reduced congestion and fewer traffic jams on I-95. The DDI will also provide additional continuous lanes, two free-flow left-turn lanes to I-95, 6-foot-wide bike lanes, additional green space, new signage, a travel information system that updates drivers on current road conditions and transportation systems management and operations enhancements.

The DDI will result in minimal environmental impact, require less land acquisition and is the most acceptable option to the community. It will provide more benefits at a lower cost, compared to a conventional interchange design.