Davidson and Rutherford Counties


TDOT is implementing a first-of-its-kind testbed to understand how all types of vehicles interact with each other and the state's infrastructure in order to advance congestion management across Tennessee. This testbed is known as the I-24 MObility Technology Interstate Observation Network, or I-24 MOTION.

The initial construction of I-24 MOTION is funded by the Federal Highway Administration (FHWA) Congestion Mitigation and Air Quality (CMAQ) Improvement Program. This project will equip a six-mile section of I-24 in the Nashville-Davidson County Metropolitan area with over 300 ultra-high definition cameras, converting those images into a digital model of how every vehicle behaves with unparalleled detail. This is all done anonymously using Artificial Intelligence (AI) trajectory algorithms developed by Vanderbilt University. Vehicle trajectory data allows us to uncover new insights into how traffic flow influences individual vehicle behavior. This groundbreaking understanding of traffic is more important than ever due to the increasing automation capability of individual vehicles, which are beginning to influence traffic flow through their interactions with conventional vehicles. By unlocking a new understanding of how these vehicles influence traffic, vehicle and infrastructure design can be optimized to reduce traffic concerns in the future to improve safety, air quality, and fuel efficiency.

Purpose and Need

The purpose of I-24 MOTION is to provide an environment for testing advanced traffic management and automated vehicle technologies in real freeway traffic. Automakers and suppliers are investing billions of dollars in adding connectivity and automation features to vehicles, forever changing safety and mobility. These technologies are often developed in the laboratory or closed-course settings. Testing in traffic captures the variability of real-world conditions and human behavior. Complementary congestion management technologies are being installed by TDOT along this same section of interstate as part of the I-24 SMART Corridor project.

Using the information gathered on this testbed, I-24 MOTION will provide insights to allow the industry to build better products and allow TDOT to better understand how to make the most out of these products for managing infrastructure assets. The first testbed user will be the U.S. Department of Energy’s sponsored research with the CIRCLES Consortium, which will study the possibility of smoothing traffic by introducing vehicles equipped with advanced driver-assist systems. TDOT envisions additional opportunities to pursue mutually beneficial uses of the testbed with industries such as those outlined below.

  • Automotive Original Equipment Manufacturers and Suppliers
  • Researchers
  • Traffic Simulation Software Developers
  • Freight and Logistics Operators
  • Infrastructure Owners
  • Intelligent Transportation Systems (ITS) Product Manufacturers
  • Enterprise Networking and Data Solution Providers

Design and Implementation

I-24 MOTION was conceptualized as an infrastructure project that would build high-resolution sensing on a section of roadway that frequently experiences congestion and a broad range of traffic conditions. The testbed sensing strategy is to deploy cameras with overlapping views across the corridor. By translating data from each camera, we can develop a complete, yet anonymous, trajectory for each vehicle with measurements made many times per second.  Below are key design & implementation details.

  • The testbed site is a six-mile section of I-24, from SR 254 (Bell Road) in Davidson County to Waldron Road in Rutherford County, long enough to provide five minutes or more of visibility per vehicle.
  • Due to the size of the project, I-24 MOTION has been divided into two smaller sections or phases.
    • from SR 254 (Bell Road) to SR 171 (Old Hickory Boulevard)
    • from SR 171 (Old Hickory Boulevard) to Waldron Road
  • Approximately 300 4K resolution cameras will be mounted on as many as sixty 110-foot poles, spaced every 500 to 600 feet along the interstate. Installing this infrastructure in a permanent capacity provides the coverage needed for many research applications and provides a location that is always available for testing technologies or running experiments.
  • As of March 2021, three poles, with a total of 18 cameras, have been constructed as part of a “Validation System” used by TDOT and Vanderbilt University to refine the project approach.
  • The design and construction of the entire testbed are forecasted for 2021-2022.