A fire engine approached a downtown Chattanooga intersection the morning of Sept. 16, but instead of relying solely on motorists to notice its flashing lights, hear its siren and get out of the way, the truck communicated directly with the traffic system.
Before the emergency vehicle reached the intersection, traffic signals changed to stop cross traffic and clear a protected path for the truck.
The demonstration near the intersection of Martin Luther King Boulevard and Market Street offered a glimpse of what City of Chattanooga and University of Tennessee at Chattanooga officials say could become a safer and more efficient transportation system – one in which vehicles, traffic signals and roadside sensors continuously exchange information.
The demonstration was part of Chattanooga Connect, a three-day conference hosted by UTC Research Institute that brought together transportation, technology, government, research and industry representatives.
According to UTC, Sept. 16’s events at Miller Plaza and Waterhouse Pavilion showcased autonomous vehicles, vehicle-to-everything communication and intersection safety technology being developed through Chattanooga’s federally funded SMART project.
The city of Chattanooga received a $2 million Strengthening Mobility and Revolutionizing Transportation, or SMART, grant from the U.S. Department of Transportation in March 2024 to plan and test connected roadway technology intended to improve mobility and safety.
Jerele Neeld, chief information officer for the city of Chattanooga, said the grant has provided a technological foundation for a larger transformation of the city’s transportation infrastructure.
“One of the big goals of the Chattanooga SMART grant is to make transportation along our health corridor safer and more efficient,” Neeld said. “And we’re looking at doing that throughout the city.”
Neeld said Chattanooga has also secured other federal transportation funding, including Safe Streets and Roads for All grants and a BUILD grant obtained with CARTA that will help bring autonomous shuttles to Chattanooga.
The connected infrastructure being installed through the SMART project could eventually help those autonomous and connected vehicles operate on city streets, he said.
Clearing way for first responders
One of Wednesday’s demonstrations showed how that infrastructure could give emergency vehicles priority at intersections.
Dr. Mina Sartipi, interim vice chancellor for research at UTC and founding director of the university’s Center for Urban Informatics and Progress, explained that roadside units installed at intersections can communicate with onboard equipment installed in emergency vehicles.
As a fire engine approaches, the vehicle sends a preemption request to the intersection. The traffic signals then turn red for other traffic, clearing the intersection before the emergency vehicle arrives.
“Cross traffic comes to a stop well before the engine arrives, which helps improve response times,” Sartipi said.
The technology uses vehicle-to-everything, or V2X, communication, a broad term for systems that allow vehicles to exchange information with other vehicles, roadway infrastructure and other parts of the transportation environment.
Stan Caldwell, director of the U.S. Department of Transportation’s SMART Grants Program, said the potential benefit extends beyond getting emergency vehicles through intersections more quickly.
“Chattanooga emergency services will get through intersections more safely and quickly, allowing them to reach emergencies sooner and potentially save lives,” Caldwell said.
Seeing beyond the driver’s view
A second demonstration tackled a different transportation problem: what a driver or an autonomous vehicle cannot see.
UTC’s autonomous research vehicle received information collected by sensors positioned at an intersection. Those sensors continuously detected objects and roadway users and transmitted that information to the vehicle.
That means a vehicle could potentially receive warning of a pedestrian obscured by another vehicle, a cyclist approaching from outside the driver’s field of vision or another roadway hazard before its own cameras and sensors detect it.
Sartipi described the concept as “cooperative perception.”
The goal, she said, is “to see beyond what the vehicle or driver can see and make our roads safer.”
Sartipi said information detected by the roadside sensors is packaged into what is known as a sensor data-sharing message and broadcast from roadside equipment to equipment aboard the vehicle.
During Wednesday’s demonstration, information about roadway users – including those the autonomous vehicle’s own sensors had not yet detected – could be viewed on a tablet inside the vehicle.
The system also allows information from traffic controllers and roadside infrastructure to be integrated with the autonomous vehicle’s operation as it moves through an intersection.
The demonstrations represent one piece of a broader effort to turn Chattanooga into a real-world testing ground for connected and automated transportation.
Neeld said the city’s work has depended on a collection of public, academic and private sector partners. In addition to UTC, he cited Leidos, Audi, Volkswagen, the Intelligent Transportation Society of America and Cisco as contributors to the effort.
He credited Chattanooga’s ability to bring those groups together as an important part of the city’s progress.
“If you’ve been around Chattanooga Connect the last couple of days, you’ve heard about Chattanooga’s secret sauce,” Neeld said.
“It’s really a willingness to work together to solve problems for the benefit of our community, whether we’re in city government, the community or the university.”
That cooperation, he said, gives Chattanooga enough scale to undertake projects that could have relevance beyond the city.
The third annual Chattanooga Connect was held Sept. 14-16 and focused on moving emerging technologies beyond experimental pilots and into practical use.
UTC said conference sessions covered autonomous transportation, artificial intelligence, quantum technology, digital infrastructure and vehicle-to-everything communications, with Wednesday’s program giving participants an opportunity to see some of that technology operating on city streets.
The presence of U.S. Department of Transportation officials also underscored the federal government’s interest in Chattanooga’s work. Michael “Rocket” Halem, principal deputy assistant secretary for research and technology at USDOT, attended the event, while Caldwell spoke before Wednesday’s demonstrations.
Caldwell said Tennessee has received $18 million through the SMART program and described Chattanooga’s project as an example of how technology can address long-standing transportation safety and mobility challenges.
“The idea behind USDOT SMART grants is to use technology to create safer, more efficient and innovative transportation systems,” Caldwell said.
From pilot project to everyday use
UTC officials said a key question now is how technology demonstrated on a limited number of streets and intersections can be expanded into an everyday transportation system.
For Chattanooga, that could eventually mean a network in which an ambulance automatically tells an intersection it is coming, a roadside sensor warns a vehicle about a pedestrian its driver cannot see, and an autonomous vehicle receives information from traffic infrastructure as it travels through the city.
Caldwell said Chattanooga’s progress is attracting attention well beyond the city.
“I want everyone to hear this,” Caldwell said. “The eyes of the nation are on Chattanooga and this project.”