MIT researchers aiming to eliminate phantom traffic jams


Researchers at the Massachusetts Institute of Technology’s (MIT) Computer Science and Artificial Intelligence Laboratory (CSAIL) are developing a method that could eliminate phantom traffic jams, using adaptive cruise-control systems.

According to the CSAIL team, there have been hundreds of academic papers looking at the problem of traffic flow, but very few about how to actually solve it. One proposed approach is to electronically connect vehicles together to coordinate their distances between each other. But platooning methods require detailed coordination and a massive network of connected vehicles. In contrast, the CSAIL team’s approach would simply require new software and some inexpensive hardware updates to vehicles.

The MIT research aims to resolve problem of phantom jams that arise without any apparent cause by removing tailgating, where drivers simply follow the vehicle in front. The team’s recently published research argues that by maintaining an equal distance between cars, the technique could allow drivers to travel twice as quickly. The CSAIL team describes the method as ‘bilateral control’, and concedes that drivers themselves are unlikely to change their forward-looking ways, so suggests that automakers update their adaptive cruise-control systems and add sensors to both front and rear bumpers to create an equidistant space around the vehicle.

According to the team, traffic would get noticeably better even if just a small percentage of all cars were outfitted with such systems. In future work, funded in part by Toyota, they plan to do simulations to test whether this method is not just faster for drivers, but also safer. The MIT team’s leader, professor Berthold Horn, first proposed the concept of bilateral control in 2013 at the level of a single car and the cars directly surrounding it. With the new paper he has taken a more macro-level view, looking at the density of entire highways and how miles of traffic patterns can be affected by individual cars changing speed, which the team refers to as ‘perturbations’.

“We humans tend to view the world in terms of what’s ahead of us, so it might seem counterintuitive to look backward,” explained Horn, who co-authored the study with postdoctoral associate Liang Wang. “But driving like this could have a dramatic effect in reducing travel time and fuel consumption, without having to build more roads or make other changes to infrastructure. Our work shows that if drivers all keep an equal distance between the cars on either side of them, such ‘perturbations’ would disappear as they travel down a line of traffic, rather than amplifying to create a traffic jam.”

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About Author


Tom has edited Traffic Technology International (TTi) magazine and its Traffic Technology Today website since May 2014. During his time at the title, he has interviewed some of the top transportation chiefs at public agencies around the world as well as CEOs of leading multinationals and ground-breaking start-ups. Tom's earlier career saw him working on some the UK's leading consumer magazine titles. He has a law degree from the London School of Economics (LSE).