I-24 Corridor Study and I-24 Monorail Assessment

Study Overview

The study identified short- and long-term solutions for improving problem spots along the entire I-24 corridor from the Chattanooga area to the Kentucky state line. The study investigated a range of multimodal solutions to address future travel demands, with emphasis on managing congestion, improving safety, maximizing the potential for freight diversion, and preserving/enhancing the corridor’s economic benefits. The effort also included an additional feasibility study for monorail system along I-24 between Nashville and Murfreesboro. 

Major Findings

The report presented the following findings: 

- Monorail technologies are capable of providing operating speeds and passenger capacities comparable to those of other modes of premium transit. They have a demonstrated history of reliable operations. 
- In areas where at-grade transit technologies or aerial heavy rail transit may pose serious physical impacts to a corridor, the lower impacts of monorail systems may offset some of the costs of building such systems.
- Side-straddle systems pose a service reliability issue - they are unable to maneuver around disabled or stopped trains, but may offer savings in costs and impacts if these issues can be resolved. 
- Cost per mile of light rail transit has growth over recent years, based on the costs of new projects that have averaged $67 million/mile, ranging from $48-91 million/mile (in 2014 dollars) in total project cost. 
- The estimated project cost to develop a monorail facility in the Southwest Corridor is approximately $1.63 billion in 2014 dollars and $2.06 billion in year of expenditure dollars for a 2020 revenue service operating date. 
- In the Southwest Corridor along the I-24 segment, there is the opportunity to build a transit line in public right-of-way in a near at-grade configuration, which would significantly reduce guideway costs. 
- Estimated annual operating costs for the monorail service is approximately $17.22 million, in 2014 dollars. This value is a function of the proposed service plan, and is dependent on hours of operation, the service frequencies during the day, and vehicle requirements based on scheduled operating speed and passenger load. 
- The total forecast transit ridership in the corridor is approximately 16,000 daily boardings when the other proposed transit service components are considered. 


The report concludes that the development of a monorail transit facility in the Southwest Corridor along the alignment identified is generally feasible, although all design details could not be addressed in this assessment. An objective assessment of project impacts needs to be conducted to determine if this particular concept causes any significant impacts that cannot be reasonably mitigated. 





  • I-24 Corridor Study and I-24 Monorail Assessment

Completion Date

  • 2015


  • Atkins

Study Partners

  • TDOT
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