TRANSPORTATION

The purpose of this study is to determine what enhancements can be programmed to improve traffic spillback onto I-95, interchange operations, safety and reduce congestion at this interchange location. Improvements are aimed at increasing the efficiency of the 45th Street and I-95 ramps while minimizing or eliminating right-of-way and bridge impacts.

The primary need for this project is to alleviate existing and future traffic congestion thereby improving safety at the interchange. Existing observations also show increased truck traffic from I-95 to Congress Avenue heading to the Port of Palm Beach contributing to the congestion within the study area.

If no improvements are made to the interchange, traffic operations and safety within the interchange area will continue to deteriorate as traffic and freight volumes increase. Also, recent studies completed in the region, such as the Concept Development Report (CDR) completed in 2014, identified operational deficiencies at the ramps, the terminal intersections and adjacent intersections at I-95 and 45th Street and determined there is a need for improvements.

A Methodology Letter of Understanding (MLOU) was prepared to document the methodology for the analysis and evaluation of this IMR. The MLOU was approved by the Florida Department of Transportation (FDOT) District 4 Interchange Review Coordinator (IRC), FDOT Central Office and Federal Highway Administration (FHWA) in January 2017. The primary basis for traffic projections in this Interchange Modification Report (IMR) are existing field traffic counts and the latest version of South East Regional Planning Model 7.0 (SERPM 7.0) with base year 2010 and horizon year 2040. The analysis years for this study include Existing Year 2015, Opening Year 2020, and Design Year 2040. The operational analysis for this study was performed using the Highway Capacity Software (HCS 2010) and Synchro 9.0. All operational analysis followed the guidelines of the Highway Capacity Manual 2010 (HCM 2010).

Several alternatives were evaluated to address the purpose and needs identified for this project. These include the No-Build Alternative, Transportation Systems Management and Operations (TSM&O) Alternative, and two Build Alternatives. All viable improvements made for the TSM&O Alternative will be carried to the Build Alternative. The two Build Alternatives evaluated in this IMR are Build Alternative 1 and Build Alternative 2. The Build 1 Alternative’s primary improvement will be widening 45th Street to 4 lanes in each direction between Northpoint Boulevard and Congress Avenue. The primary improvement for Build Alternative 2 will be reconfiguring the current diamond interchange to a Diverging Diamond Interchange (DDI).

As part of this study, an existing crash analysis was performed. The data provided from FDOT CARS database shows rear end, sideswipe and angle crashes are the most prominent crash types within the region and are indicative of congested roadway conditions. The Recommended Build Alternative shows improved traffic operations and safety within the project study area when compared to the No-Build Alternative due to less delay, reduction in congestion and improved geometric design to prevent angled crashes along 45th Street.

Based on the evaluations of the No-Build and Build Alternatives, the recommended alternative, for approval in this study, is Build Alternative 2. The Recommended Alternative will incorporate viable TSM&O improvements and will be developed further as the Project Development and Environment (PD&E) project progresses.

This IMR has been developed in accordance with the FDOT Policy No. 000-525-015: Approval of New or Modified Access to Highways on the Strategic Intermodal System (SIS), FDOT Procedure No. 525-030-160: Approval of New or Modified interchange access to limited access facilities on SIS, Interchange Access Request User’s Guide (IARUG), and the FDOT Traffic Forecasting Handbook (Procedure No. 525-030-120).