July 27


Autonomous Vehicles Mix May Eliminate Phantom Traffic Jams

By Mike Spack

July 27, 2017

autonomous vehicle, bottleneck, phantom traffic, traffic jam, traffic research

By Mike Spack, PE, PTOE

Exciting new research sponsored by the National Science Foundation and conducted by Rutgers-Camden, Temple, Arizona, and Illinois Universities shows that a few autonomous vehicles in the traffic stream could eliminate pesky phantom traffic jams.

According to Daniel Work, assistant professor at the University of Illinois at Urbana-Champaign, who was a lead researcher in the study –  “Our experiments show that with as few as 5 percent of vehicles being automated and carefully controlled, we can eliminate stop-and-go waves caused by human driving behavior.”

Here are key details from a University of Illinois brief:

  • Phantom Traffic Jam = human drivers naturally creating stop-and-go traffic, even in the absence of bottlenecks, lane changes, merges or other disruptions.
  • Researchers conducted field experiments with a single autonomous vehicle and at least 20 human driven vehicles circling the track.
  • By controlling the pace of the autonomous car, they smoothed traffic flow for all the cars.
  • They 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.
  • The autonomous vehicle control strategies used were simple and easy to implement.

Here’s an awesome video of the test track experiment demonstrating the concept:


Special thanks to Daniel Work who emailed me about the team’s research.  This is a very consequential finding and I’m happy to be able to share it with you.

p.s.  Sugiyama, et al famously proved traffic jams can be caused by humans without the presence of a physical bottleneck, aka Phantom Traffic Jams.  Here’s a video of the phenomenon created on a test track: “Traffic Jam without Bottleneck.”


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Mike Spack

My mission is to help traffic engineers, transportation planners, and other transportation professionals improve our world.

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