The data collected from the six-mile stretch of Interstate 24 near Nashville will allow transportation agencies, carmakers and researchers to “study current and emerging operational strategies and technologies at a resolution not currently available,” said Brad Freeze, director of traffic operations at the Tennessee Department of Transportation (TDOT).
The testbed is known as the I-24 Mobility Technology Interstate Observation Network, (I-24 MOTION). For starts, it will be equipped with 300 high-definition cameras which convert traffic images into a digital model of how traffic flows.
TDOT will not save the video data and instead will convert it into “vehicle digital trajectories of the traffic flow in real time,” said Freeze.
“The saved digitized version of the data will not contain any personal identifiable information,” he added. “It is a digital reproduction of the traffic flow with high-resolution vehicle trajectories.”
Worked into this traffic flow will be a small number of connected vehicles equipped with varying degrees of automation.
This study group is part of a consortium of research institutions like University of California, Berkeley Institute of Transportation Studies (ITS) participating in a project called Congestion Impacts Reduction via CAV-in-the-loop Lagrangian Energy Smoothing, better known as the CIRCLES Project. Other universities include Rutgers University-Camden, University of Arizona, Temple University and Vanderbilt University. Nissan, Toyota and General Motors are the participating automakers.
The CIRCLES Project is part of a $3.5 million U.S. Department of Energy cooperative research agreement.
“Imagine all you could do in terms of using that testbed to understand how self-driving vehicles impact the freeway,” said Alexandre Bayen, ITS director.
“And so that turned out to be the perfect testbed for us,” he added, referring to the Tennessee I-24 MOTION project. “For the first time, we will be able to see, with very high resolution, the impact of what we’re doing.”
The I-24 MOTION corridor sets up a space to test and study advanced traffic management technologies, and how connected and collaborating vehicles can contribute to a smoother flow of traffic, reducing the stop-and-go patterns which consume more fuel and add to greenhouse gas emissions.
Researchers from the CIRCLES Project say greenhouse gases can be reduced 10 percent if only 5 percent of cars are automated and communicating with each other, due to the smoother flow of traffic.
“And so, what we’re asking ourselves is, with a small proportion of vehicles acting as flow-smoothers, what would that produce in terms of improvements of the negative externalities of congestion,” said Bayen.
The particular section of I-24 selected as the testbed made sense, in part, because of the connected vehicle technologies already deployed in the area, said Freeze. There’s also lane management and dynamic speed control systems in place, along with ramp-metering systems.
“In addition, this section of freeway has a high-capacity backbone of communication infrastructure in place,” Freeze added, referring to the TDOT-owned fiber-optic communications.
“This testbed will help TDOT and others better understand strategies used to manage traffic, and support reliable transportation,” said Freeze, via email. “It will also enable the transportation community in the study of driver behavior and traffic safety countermeasures.”
Bayen stressed the research gleaned from the testbed is not aimed at solving traffic congestion, but understanding it more thoroughly and realizing opportunities for connected vehicle environments.
“We’re not changing the demand, or the travel time, or the total number of vehicles … We’re changing the way things flow,” Bayen explained.
“We believe that with simple things, where you just adjust the speed of your vehicle, based on information from shared cooperation, you could greatly improve the energy efficiency of the freeway,” he added.
