Florida Department of Transportation (FDOT) District 1 has requested that the interchange of State Road 70 (SR 70) at Interstate 75 (I-75) be modified. This modification converts the previously approved diamond interchange to a hybrid diamond interchange. The study area along I -75 extends from University Parkway to SR 64, a distance of 7.33 miles, and along SR 70 from west of Tara Boulevard to Braden Run Road, a distance of 2.006 miles.
The purpose of this Interchange Modification Report (IMR) is to reevaluate the future traffic operations at the I-75/SR 70 interchange based on the revised population/traffic growth projections, and reevaluate the need for the diamond interchange configuration recommended by the Project Development and Environmental (PD&E) study and the Systems Interchange Modification Report (SIMR). The need for this IMR is to evaluate alternatives, including the No-
Build alternative; Transportation Systems Management & Operations (TSM&O) alternatives; the 2012 I-75 SIMR preferred alternative; and an additional interchange alternative, to identify the most suitable interchange configuration to meet the demands of future travelers, while minimizing project costs and impacts.
A Methodology Letter of Understanding (MLOU) was prepared to document the methodology for the analysis and evaluation for this Interchange Modification Report (IMR). The MLOU was approved by the District Interchange Review Committee, FDOT Systems Planning Office and Federal Highway Administration (FHWA) in May 2013. A signed copy of the MLOU is provided in Appendix A. The following sections summarize the methodology stated in the MLOU.
The adopted 2007 Sarasota/Manatee Counties (SMC) Validation Model and 2035 SMC Cost Feasible Model have been utilized for the purposes of forecasting future travel demand. Other currently approved development plans that may impact the study area were obtained from Manatee County. The recently adopted 2035 SMC Cost Feasible Model was used to perform a sub-area validation for the defined project study area. The sub-area validation meets the requirements
of the Florida Standard Urban Transportation Modeling Structure (FSUTMS)Model Update Task Force. This procedure is also consistent with the recommendations from the Interchange Handbook Technical Resource Document (TRD) 8 – Travel Demand Model Selection. If required, adjustments to the model were made as noted within the Interchange Handbook TRD Section 8.This is also consistent with Section 3.8.2 of the 2012 FDOT Project Traffic Forecasting Handbook (Figures 3.3 and 3.4) and the FSUTMS-Cube Framework Phase II Model Calibration and Validation
Standards dated October 2, 2008.
The travel demand forecasts from the sub-area validated 2035 cost feasible model were extrapolated using growth rates to obtain design year (2038) traffic projections. The growth rates were developed based on comparison of historic trends, 2012 existing traffic counts and forecasted model output volumes.
The interchange modifications recommended in this IMR are intended to provide improved interchange operations at the SR 70 interchange. Additional recommendations enhance the arterial operations of SR 70. The following alternatives have been developed and analyzed for this IMR, No-Build with Special Use Lanes (SUL) and one auxiliary lane on the General Use Lanes (GUL) for each direction, Build - diamond interchange alternative and Build - hybrid diamond
interchange alternative. The alternatives were analyzed to assess their effectiveness in meeting the future travel demand of the study area, as well as the physical and social impacts, and safety and environmental considerations associated with each alternative.
SR 70 interchange (MP 3.712) is 3.71 miles north of I-75/University Parkway interchange and is 3.62 miles south of the I-75/SR 64 interchange. The study boundary on SR 70 is from east of Tara Blvd. (MP 4.807) to Braden Run Road (MP 6.813), a distance of 2.006 miles. The following intersections and segments are included in the study area.
SR 70 @ 55th Avenue East
SR 70 @ Lena Road
SR 70 @ Tara Boulevard/Creekwood Boulevard
SR 70 @ I-75 SB Ramps
SR 70 @ I-75 NB Ramps
SR 70 @ Ranch Lake Boulevard/87th Street
SR 70 @ Braden Run Road
Existing Roadway Segments
SR 70 between Tara Boulevard and I-75 (MP 4.903–5.116)
SR 70 between I-75 and Ranch Lake Boulevard (MP 5.645–5.861)
I-75 between University Parkway and SR 70 (MP 0.324–3.408)
I-75 between SR 70 On/Off Ramps (MP 3.409–4.009)
I-75 between SR 70 and SR 64 (MP 4.010–7.0)
The proposed improvements to the interchange will enhance traffic operations on SR 70 and have no adverse impacts to I-75. The proposed interchange will remain inside the existing SR 70 interchange right-of-way thereby eliminating any additional environmental impacts.