Researchers from MIT’s Computer Science and Artificial Intelligence Laboratory (CSAIL) believe there would be fewer phantom traffic jams if motorists stopped tailgating.
Specifically, the team argues that if motorists kept an equal distance between the cars in front of and behind – an approach that MIT professor Berthold Horn describes as “bilateral control” – then journey times would improve thanks to fewer phantom traffic jams, which occur for no obvious reason.
“We humans tend to view the world in terms of what’s ahead of us, both literally and conceptually, so it might seem counter-intuitive to look backwards,” said Horn, who co-authored a paper on the subject of traffic congestion 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.”
According to MIT, Horn understands that drivers themselves are unlikely to change their forward-looking ways anytime soon, so he suggests that car companies update their adaptive cruise-control systems and add sensors to both their front and rear bumpers.
According to Horn, traffic would get noticeably better even if just a small percentage of all cars were outfitted with such systems. In future work part-funded by Toyota, he plans to do simulations to test whether this method is not just faster for drivers, but also safer.
According to the CSAIL team, for decades 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 so-called “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.
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 main road systems and how miles of traffic patterns can be affected by individual cars changing speeds, which his team refers to as “perturbations”.
“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 amplify to create a traffic jam,” says Horn.
Tailgating, lane discipline and reaction to braking in front… Very interesting research and needed, especially for UK roads!
Even if I say so myself, it has been obvious to me for years that tailgating and the subsequent braking by those that do it, causes phantom traffic jams on motorways. Multiply this with vehicles travelling at vastly different speeds, random lane changes etc and it is inevitable. Add to this mixture those who ‘dab’ their brakes to switch off the cruise control, causing the tailgater to brake and before you know it the speed vehicles are travelling at drops to a crawl. Not sure why it took a group of researches to work this one out. The clever bit will be stopping it from happening in the first place and as the drivers who tailgate are clearly not too clever themselves, automatic methods are the way forward. Alternative introduce average speed cameras and drop the maximum speed limit at the same time.
“traffic jams, which occur for no obvious reason: …”
but a US colleague who travelled the New Jersey freeway and the Skuykil Expressway around Philadelphia (known locally as the Sure-kill) believed that their structure could be likened almost exactly the the modus of movement of the earth-worm: expanding and contracting waves of segments of the body moving relative to each other and bunching and extending. Seen from above, that is exactly what ‘jams’ look like. How often have we noted that Nature has been there long before we simple humans!