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I-75 at Corkscrew Road (CR 850)

Download the Final Study (PDF, 2.5MB)

Executive Summary

The purpose of this IOAR is to provide the required technical documentation for obtaining FHWA approval for improvements at the I-75/Corkscrew Road interchange in Lee County. The current interchange is a diamond interchange with signal-controlled operation at both ramp terminal intersections.

The primary basis for traffic projections in this IOAR is the latest version of the District One Regional Planning Model (D1RPM) which has a base year of 2010 and a cost feasible (forecast) year of 2040. The analysis years for the study include Existing Year 2016, Opening Year 2019, and Design Year 2029. The operational analysis for this study was performed using Highway Capacity Manual (HCM) 2010 procedures and VISSIM microsimulation software.

The I-75/Corkscrew Road interchange serves as the primary I-75 access point for the Villages of Estero. The interchange ramp terminal intersections currently experience significant delays and queues for critical left turn movements during peak hours.

Two alternatives will be evaluated in this IOAR (Build Alternative and No-Build Alternative). The Build Alternative consists of additional left turn lanes accessing the I-75 on-ramps (resulting in dual left turn lanes in both directions), additional queue storage lanes along the eastbound and westbound approaches to the interchange, extended acceleration/deceleration lanes for ramp merge/diverge operations along I-75 mainline, replacement of high mast lighting at the interchange, and buffered bicycle lanes along Corkscrew Road within the interchange area. The No-Build Alternative would maintain the current facility with no improvements.

FDOT is requesting approval of the Build Alternative as part of this IOAR. Currently, the final design phase is funded through FDOT, District One, and is currently ongoing. No right of way acquisition is required for the Build Alternative. Letting for construction is currently targeted for FY 2019.

The proposed improvements at the I-75/Corkscrew Road interchange will provide significantly better operations along Corkscrew Road, at the ramp terminal intersections, and at the I-75 ramp junctions with no significant negative impacts.

The comparison of the No-Build and Build Alternative shows that the proposed improvements will provide better and safer operating conditions by reducing delay and queuing at the study interchange. These improved operating conditions will result in a reduction of the likelihood of rear-end and sideswipe crashes, resulting in safer conditions compared to the No-Build Alternative.

This IOAR has been developed in accordance with FDOT Policy No. 000-525-015: Approval of New or Modified Access to Limited Access 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, the Interchange Access Request User’s Guide (2015) and the FDOT’s 2014 Project Traffic Forecasting Handbook (Procedure No. 525-030-120).

Purpose and Need

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I-75, a north/south facility, is an integral part of the Strategic Intermodal System (SIS) providing for high-speed, high-volume traffic movements within the State. The 2002 I-75 PD&E Study and accompanying SIMR recommended improvements to the Corkscrew Road interchange. traffic study evaluated the previously proposed SPUI interchange alternative along with several other build alternatives; the result of this study was the recommendation of additional detailed analysis including microsimulation to determine the preferred concept for the I-75/Corkscrew Road interchange.

In 2016, a traffic study was initiated with the intent to further evaluate the “ultimate” interchange improvements (evaluating SPUI, DDI and improved diamond alternatives) using a Design Year of 2044 and an Opening Year of 2024. During the course of that study, a determination was made by the District to consider relatively minor “interim” improvements to determine how many years of serviceable life could be gained. A series of interim improvements were evaluated and they were shown to provide acceptable operations through the year 2029. Therefore, a determination was made to move forward with interim improvements at this interchange.

The purpose of this IOAR is to evaluate the future traffic operations at the I-75/Corkscrew Road interchange based on the revised population/traffic growth projections, to evaluate the need for the improvements recommended by previous studies, and to determine the preferred configuration for the subject interchange using detailed microsimulation-based analysis.

Recommended Alternative

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Please see the attached recommended alternative

Travel Time Savings

Safety Benefits