New research suggests that the presence of just a few autonomous vehicles could improve the driving of human drivers, reducing accidents and improving fuel economy
“Our experiments show that with as few as five percent of vehicles being automated and carefully controlled, we can eliminate stop-and-go waves caused by human driving behaviour,” said Daniel Work, assistant professor at the University of Illinois at Urbana-Champaign.
The research was conducted by a multi-disciplinary team with expertise in traffic flow theory, control theory, robotics, cyber-physical systems, and transportation engineering, from Rutgers University, Temple University and the University of Arizona, Tucson, as well as the University of Illinois.
The team conducted field experiments in Tucson, in which a single autonomous vehicle circled a track continuously with at least 20 other human-driven cars. Under normal circumstances, human drivers naturally create stop-and-go traffic, even in the absence of bottlenecks, lane changes, merges or other disruptions, Work said. This phenomenon is called the “phantom traffic jam.”
Researchers found that by controlling the pace of the autonomous car in the study, they were able to smooth out the traffic flow for all the cars. For the first time, researchers demonstrated experimentally that even a small percentage of such vehicles can have a significant impact on the road, eliminating waves and reducing the total fuel consumption by up to 40 percent. Moreover, they found that conceptually simple and easy to implement control strategies can achieve the goal.
"Before we carried out these experiments, I did not know how straightforward it could be to positively affect the flow of traffic," said Jonathan Sprinkle, Associate Professor in Electrical and Computer Engineering at the University of Arizona.
"I assumed we would need sophisticated control techniques, but what we showed was that controllers which are staples of undergraduate control theory will do the trick."
The researchers say the next step will be to study the impact of autonomous vehicles in denser traffic with more freedom granted to the human drivers, such as the ability to change lanes.
[The driving experiments at the University of Arizona. Photo: University of Illinois]
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