Can we banish the phantom traffic jam? Intelligent cars will be able to head off congestion problems before they happen.

Can we banish the phantom traffic jam? Intelligent cars will be able to head off congestion problems before they happen.
Bangkok Traffic at Night

The cause may be an accident, or construction, or the crush of mid-sized SUVs leaving a Billy Joel concert, but if you’re part of the traffic flow, you’re part of the problem.

With the same methods, drivers working cooperatively could significantly and continuously reduce traffic backups on highways.

Error-Prone is meant to show how much safer and more efficient self-driving cars can be on the road; indeed, when all the cars are centrally controlled to travel at the same speed in the same path, they do not crash.

The game is also a lovely demonstration of something called a phantom traffic jam, one of those everyday occurrences in which traffic backs up for no apparent reason.

This wave of slowed traffic moves backwards along the roadway, simultaneously growing larger and slowing down until the parkway becomes a parking lot.

The Japanese scientists who made the video above were the first to prove the existence of these waves in traffic flow.

The technology was seen as the solution, providing a future in which “Electronic driving assistance hardware that helps drivers to accelerate and decelerate more smoothly, and thus to make the occurrence of jamitons less likely.” This isn’t purely academic: Jamitons cause stop-and-start traffic, which leads to accidents, which result in serious delays and occasionally serious injury.

Now, we are on the cusp of autonomous vehicles; we expect that technology to save us from traffic jams.

“In 1996, I decided to singlehandedly change attitudes toward driving,” says William Beaty, referring to the year he started the website

“Rather than have to type out three paragraphs every time someone started telling me how people should drive, I just created an HTML page.” On that page, Beaty set forth a theory that likened phantom traffic jams, as well as those that linger after an accident is cleared, to shockwaves.

Highway patrol cars often sweep into traffic to slow the flow for seemingly no reason at all; often, they’re providing a traffic break to stop a wave travelling back from an accident miles ahead. “Belgium and Netherlands have for about 15 years used pace-cars – a method they call ‘Blokrijden’ – whenever the whole country goes on vacation at the same time,” notes Beaty.

Even though they may know, empirically, that allowing distance between cars and not racing forward just to slam on your brakes at a stoppage will get us and the rest of the humans behind us to destinations more quickly, the truth is we probably won’t, especially if it means that some other jerk is going to arrive at his destination 2.35 seconds before we do.

He adds, “I suspect that if a driver finds that their ACC prevents their aggressive behaviour, they’ll simply turn it off.” It probably doesn’t help the cause that vehicles equipped with ACC tend to be the sorts of vehicles that have luxe leather interiors and throbbing, feline engines, and are not known to have drivers versed in the art of selflessness.

Dr. Larry Head, of the newly formed Transportation Research Institute at the University of Arizona, sees two R&D approaches to solving the traffic jam.

“Vehicles will talk to each other to share information ten times per second. Each car will know what the vehicles around it are doing much faster than a human could sense and react. This will allow vehicle-based applications, such as cooperative adaptive cruise control, to assist human drivers to achieve significant improvements in safety.” V2V technology is on the horizon; in the US, the National Highway Transportation Safety Board has made implementation a priority, and the Cadillac CTS will roll out with the technology in 2017.

“Connected vehicles are an important step towards reducing the 34,000 deaths due to traffic crashes in the US,” says Head. “We believe the benefits will be similar to seat belts.”

“Another application, called Speed Harmonization, will set the speed limit dynamically to smooth the flow,” says Head. “An application, called Queue Warning, will alert vehicles and drivers of shockwaves downstream so that drivers can be alert and react more quickly if needed.” This technology, which dampens out those pressure waves by slowing all drivers to the roadway’s average speed, has recently replaced the Low Countries’ Blokrijden, and it’s even been applied to the very same section of highway that William Beaty drove when videoing his first driving experiments, both to great success.

“The second research path is the autonomous, or self-driving vehicles,” says Head. “Currently, these two research paths are independent. I believe that this is due to the need of autonomous vehicles to operate in all environments, with or without other connected cars. Until the market penetration of connected vehicles is sufficient to benefit autonomous vehicles, there will likely be little integration.”

The self-driving car, with complete market penetration, remains the holy grail of smooth and safe traffic flow.

In the quest for perfect traffic flow, we humans can’t seem to stay out of our way.