Interstate 75 Interchange at Interstate 24 - Phase IIHamilton County
The existing Interstate 75/Interstate 24 interchange is a heavily traveled corridor that serves Tennessee and Georgia. Both I-75 and I-24 provide a direct connection to downtown Chattanooga, Lookout Mountain and other area attractions, while I-24 also serves as a direct link between I-75 and I-59.
Continued growth and increased traffic volumes along the I-75 and I-24 corridors have increased concerns for the safety of the interchange. A review of the project area revealed operational deficiencies, including poor ramp geometry and insufficient merging distances. Interchange modifications are necessary to increase capacity, correct merge points, and enhance ramp function. The planned design will improve the safety and operation of the interchange, while providing a facility that meets traffic demands.
The planned improvements for Phase II of the interchange at I-75 and I-24 consist of:
- I-24 from Germantown Road to Spring Creek Road will be widened and entrance and exit ramps to North and South Terrace will be reconfigured.
- I-75 from west of the CSX Railroad overpass to the East Brainerd Road interchange will be widened to five lanes.
- The Interchange ramps which were reconstructed during Phase I will be resurfaced and restriped to create additional travel lanes.
The improvements will increase the safety, efficiency, and operation of the interstate, while providing congestion relief and addressing the deficiencies of the existing interchange.
Current Status: Construction
Construction start: Spring 2023
Estimated completion*: 2025
Temporary lane closures will be in place nightly for the duration of the project. During these lane nightly lanes closures, at least one lane will remain open in each direction on both I-24 and I-75 (Sunday through Thursday, between 9:00 p.m. and 6:00 a.m. local time).
Entrance/exit ramps within the project limits will be temporarily closed when they undergo reconstruction. However, at least one entrance lane and one exit will always remain open in each direction. All interstate-to-interstate ramps, as well as the Welcome Center, will remain open for the duration of this project.
The South Moore Road bridge over I-24 and McBrien Road bridge over I-24 will be replaced as part of this project. The contractor is allowed to completely close each bridge during their replacement; however, only one bridge will be closed at a time. During these closures, signage will be in place and traffic will be detoured around.
History and Background
Due to funding constraints, TDOT has chosen to split improvements to the I-75/I-24 interchange in Hamilton County into two phases. Phase I completed the reconstruction of the interchange itself and part of I-75 North of Chickamauga Creek. Phase I also had to meet (tie back into) existing conditions on I-24 West, which resulted in the I-75 North to I-24 West ramp being reduced to one lane prior to the Spring Creek Road underpass. Phase II will add lanes to I-75 and I-24 in both directions approaching the merge, and all interchange ramps will be widened to at least three lanes in each direction (including the I-75 North to I-24 West ramp).
TDOT completed Phase I improvements to the I-75/I-24 interchange in Hamilton County in the Summer of 2021. The project was successfully completed on time and on budget.
Phase 2 of the modification and reconstruction of the at I-75 Interchange and I-24 in Hamilton County consists of three segments.
Segment 1 – I-24 from Germantown Road to Spring Creek Road. Existing I-24 is primarily a six-lane, controlled-access facility, separated by a concrete barrier wall with a right-of-way width of approximately 500 feet. Proposed improvements in this segment include: interstate widening; modifying the entrance and exit ramps to North and South Terrace; widening the westbound exit ramp to South Moore Road; replacing the concrete pavement with asphalt; replacing the storm drainage system, median barriers, guardrail, signing, and lighting; constructing new retaining walls and noise barriers; and replacing the South Moore Road and McBrien Road overpass bridges.
Segment 2 – I-75 is primarily an eight-lane, controlled-access facility, separated by a concrete barrier wall with a variable right-of-way width of approximately 300 to 600 feet. Proposed improvements in this segment include: interstate widening; widening the East Brainerd Road to I-75 southbound entrance ramp; replacing median barriers, guardrail, signing, and lighting; rehabilitating existing concrete pavement; and replacing the I-75 bridge over the CSX railroad.
Segment 3 – Interstate-to-Interstate ramps within the I-75 and I-24 interchange. Ramps previously reconstructed during Phase I of the project will be resurfaced and restriped to create additional travel lanes. Overhead signs will be adjusted to match the new interchange layout.
Both Phase I and Phase II of this project were completed using the Design-Build alernative delivery mechanism, an alternative to the traditional Design-Bid-Build project delivery method. Design-Build combines various portions of the design and construction phases into a single contract, whereas Design-Bid-Build separates design and construction into separate contracts and separate work. Design-Build can provide a more unified flow of work from conception to completion by allowing the contractor to use innovative solutions that improve project delivery time, reduce project costs, and reduce impacts to drivers. TDOT is utilizing the design-build concept to expedite project delivery and streamline design processes for the I-75/I-24 interchange project and is expected to save over a year of construction time compared to traditional construction methods.
In addition to utilizing the Design-Build method, TDOT has allowed the contractor to use other techniques to expedite completion of this project. This includes allowing the contractor to conduct construction activities 24/7 and use a technique called rubblization, both of which allow work to be completed faster but do result in a noisier project site,
Public Involvement and Engagement
To receive email updates on this project, including lane closure information, follow the instructions below.
- Click the email link: LISTSERV@LISTSERV.TN.GOV
- In the message body, cut and paste the following information: Subscribe JJ_75-24_PHASE2
- Send email. (no subject line necessary)
This website will be one of the principal means of public involvement and feedback. Public questions, comments, or concerns about this project can be submitted to: TDOT.Comments@tn.gov.
Project Imagery & Visuals
Maps (JPEG images with design rendering overlay)
Key Project Milestones
The following is a reflection of various aspects of the project phases as they have occurred or will occur for the planned I-75/I-24 Phase 2 Interchange improvements.
Completion of Design Plans
Late 2023 (estimated)
Late 2025 (estimated)