NASHVILLE, Tenn. (WKRN) — Drivers who use Interstate 24 between Murfreesboro and Nashville are no strangers to its daily challenges. According to the Tennessee Department of Transportation, traffic volumes have increased by more than 60% in the Murfreesboro-Rutherford County segments of l-24 since 2005.

“We have a chief engineer who likes to say, you can’t always widen your way out of growth,” said TDOT Spokesperson Rebekah Hammonds. “There’s just so many technological advances that we could be and want to be utilizing here in Tennessee.”

TDOT finished designing Phase one of their I-24 SMART Corridor project in 2018 and are now approaching the finish line for Phase 2.

Phase 2 included 67 overhead gantries being installed over the east and westbound lanes of the interstate between mile markers 53 and 70. Each gantry will have overhead message boards over each lane that will display yellow and red exes, green arrows, and the current recommended speed limit depending on traffic conditions.

(Courtesy: TDOT)

“Like many projects that we are working on right now, we are seeing delays in materials, even material shortages,” said Hammonds. “We have had some delays on some of the gantries, it has not necessarily shifted the project significantly in its timeline, but we are seeing a very small delay.”

She explained that once all the gantries are up, they’ll run tests before having them operational around December or early 2023.

That same area of I-24 is also the focus of project that TDOT leaders hope will also help ease congestion: The I-24 Mobility Technology Interstate Observation Network (MOTION). Vanderbilt University and TDOT installed over 294 ultra-high definition cameras on a four-mile section of I-24 in the Nashville-Davidson County Metro area. The imagery is processed anonymously by computer vision algorithms, rather than having human beings look at the data, and it analyzes the paths of vehicles and how they interact.

“That is just so important to capture just the extremely obvious, but frustrating things like phantom traffic jams: ‘I’m stuck in traffic and I have no idea why’. Well, collectively, the way that you and I and everyone else drives, one person makes a small mistake, the driver behind it amplifies that mistake. And all of a sudden, the freeways come to a complete shutdown,” said Dan Work, PhD, Associate Professor of Civil and Environmental Engineering at Vanderbilt University. “I-24 MOTION was exactly designed to be able to collect the data to try to understand those phantom traffic jams. You can’t see them with classical sensing technologies. If you can’t measure it, I don’t know how you’re supposed to improve it.”

The project’s website called their efforts ‘groundbreaking’ and ‘more important than ever’ because there’s an increased presence of automation capability in individual vehicles, that are beginning to influence traffic flow through their interactions with older vehicles. Keep in mind, they’re not referring to self-driving vehicles.

“So many people have the dash that is Bluetooth enabled or will alert you if you are swaying over the lanes, will alert you if you’re too close to the person ahead of you or behind you. That is the kind of technology we’re talking about,” Hammonds said. “You may not realize it but your vehicle on a constant basis is communicating with systems like traffic lights and systems on the roadway and other vehicles around it. So we’re going to be capturing that and then learning from it.”

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The significant portion of the construction has been completed for I-24 MOTION and officials will now be conducting tests ahead of launching the cameras this Fall.

“We are so excited to be working with Vanderbilt to get all the research for 24 MOTION, and to then take it to that next step and implement that research and those cameras into this project (SMART Corridor) so we’re able to not only have two projects work hand in hand, but to see kind of the rubber meets the road, if you will, you know, we want to be in the forefront of how technology is intertwined into the transportation industry,” said Hammonds.


Their goal is to have the data available to help automakers designing vehicles, and to help transportation officials in other metro areas improve their traffic challenges as well. We asked how the information they learn in Nashville could be applied elsewhere.

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“A lot of the traffic is made up of a complexity of how people drive and what kind of infrastructure you have,” said Work. “I think the real challenge across the planet right now is trying to understand exactly how individual vehicles behave and how that scales up into traffic. All of the technology companies that are highly focused on getting cars to drive by themselves are not yet at the point where they start thinking about what happens when you have thousands of them per hour that are running down the freeway. But that’s exactly what traffic is. It’s a collection of a lot of individual things doing things at scale. And so I-24 MOTION exactly is designed to see those different spectra, like how individual vehicles interact, and then how that manifests in traffic.”

Learn more about the I-24 SMART Corridor project HERE. Learn more about the I-24 MOTION project HERE.