TDOT Using Design-Build Method on I-75/I-24 Interchange Project
The Tennessee Department of Transportation is decreasing congestion and improving safety with a design-build project underway to modify the heavily traveled interchange of I 75/I 24 in Chattanooga. This is a system-to-system interchange connecting I-75 to I-24 and serves traffic as a direct connection to downtown and other area attractions. 2019 annual average daily traffic (AADT) on I-24 was 125,000 vehicles per day and 130,000 vehicles per day on I-75. These numbers are projected to increase as the surrounding communities continue to grow.
The purposes of the modifications are to decrease congestion, improve substandard ramp geometry, improve safety, increase interstate capacity, and improve traffic operations. TDOT is using the design-build concept to expedite project delivery and streamline design processes.
The contract was awarded in December 2018 and construction began in January 2019. The project is slated for completion in late summer 2021.
Work is progressing well. Stage one is complete. Several ramps were constructed alongside the existing highway ramp lanes. The design strategically took advantage of the empty space within the existing interchange to maximize the amount of construction that could be accomplished without interfering with traffic patterns.
Stage two of the project is currently underway and will continue into the spring of 2021. The end of stage two will see traffic for all ramps placed into its final alignment. Most significantly, this change will include a new traffic pattern at the I- 75 NB split where the I-24 WB ramp will be converted from a left-hand exit to a more conventional right-hand exit.
The I-75/I-24 interchange modification project was one of 962 critical transportation projects included in the 2017 IMPROVE Act legislation.
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