In September 2019, the Florida Department of Transportation received approval from the Federal Highway Administration for the Systems Interchange Modification Report Reevaluation, supporting the implementation of a new concept, hereafter referred to as the Design Build Concept. The improvements are along I-595, extending from State Road 7 to the I-95 Interchange in Broward County, Florida.
This SIMR Reevaluation compares traffic operations for the 2019 SIMR Reevaluation Design Build Concept, and the 2017 SIMR Reevaluation. The recommendations from the previous SIMR will be referred to as the RFP Concept.
The purpose of the 2019 SIMR Reevaluation was to modify the existing system to system connection between I-595 and I-95 by providing direct connections between the I-95 Express Lanes and the General Use and Reversible Express Lanes on I-595.
The Design Build Concept proposes the following improvements:
At the I-95 and I-595 Interchange, merge and diverge points were shifted for the Southbound to Westbound and Eastbound to Northbound movements. In addition, a braided ramp was eliminated that provided redundant access from I-95 Southbound Express Lanes to Westbound I-595 General Use Lanes. Lastly, the State Road 7 and Florida's Turnpike traffic was separated by developing a new two-lane ramp from I-595 Westbound to Florida's Turnpike further downstream.
Next, the bridge width for Westbound I-595 over Eastbound State Road 84 was increased to provide six through lanes. The next improvement added a new one-lane ramp from Florida's Turnpike to Eastbound I-595. Lastly, the Eastbound I-595 to Eastbound State Road 84 ramp was relocated to the west by approximately 1,400 feet.
Along the I-595 Mainline a two-lane exit from Eastbound I-595 to the I-95 Express Lanes was provided. In addition, the I-595 Express Lane merged to the outside in advance of the connection with Eastbound I-595 General Use Lanes to create a 5-lane Eastbound I-595 section which then accepts the merge from the newly created single-lane ramp. This 5-lane section continues east until the single lane addition of the ramp from State Road 7 Interchange which creates a 6-lane section on Eastbound I-595. Lastly, the Southbound I-95 Express to Westbound I-595 ramp terminal condition was changed from a left-side merge along Westbound I-595 to a lane addition and changed the Northbound I-95 Express to Westbound I-595 ramp terminal condition from a lane addition to a left-side merge approximately 1,000 feet downstream from the Southbound I-95 Express to Westbound I-595 lane addition.
It should be noted that this Reevaluation provides the traffic operational analysis for the design year only to demonstrate that the Design-Build Concept is equal to or better than the RFP Concept.
An analysis of the 2019 SIMR Re-evaluation Design-Build Concept was performed in accordance with the related MLOU and the FDOT's Interchange Access Request Users' Guide.
The 2019 SIMR Reevaluation Design-Build Concept satisfies the FHWA's Policy on Access to the Interstate System and provides better traffic operations when compared to the RFP Concept.
The 2019 SIMR Reevaluation Design-Build Concept generates higher operating speeds at the On-Ramp from Florida's Turnpike to I-595 Eastbound. The On-Ramp, in Design-Build Concept, operates at speeds of 40 miles per hour or higher. While, the On-Ramp, in the RFP Concept, operates at speeds below 30 miles per hour.
For the RFP Concept, the Demand-to-Capacity ratio of the weaving section between the on-ramp from Southbound I-95 General Use Lanes and off-ramp to State Road 7 and Florida's Turnpike is greater than 1 while in the Design-Build Concept ratio was less than 1.
One key objective of the Design-Build Concept was to improve the weave length and or number of lane changes associated with the weaving segments in the RFP Concept. The Design-Build Concept improves the overall weaving section distance per lane change maneuver by 7 percent compared to the RFP Concept.
The objective of this safety analysis was to estimate and compare the future crash potentials of the RFP and Design-Build Concepts. The Design-Build Concept is predicted to reduce future crashes by 10 point 7 crashes per year.
Based on the findings, the 2019 SIMR Reevaluation Design-Build Concept is offered to replace the previously approved 2017 SIMR Reevaluation RFP Concept. This SIMR Re-Evaluation was approved by FDOT Central Office and Federal Highway in July 2019.