Red, yellow, green… and white? Research shows that adding a fourth traffic light color could make traffic jams a thing of the past
Nothing is more annoying than being stuck in traffic and watching the clock tick away.
But the days of being stuck in traffic could be a thing of the past – if cities changed their traffic lights to a fourth color.
That’s according to researchers at North Carolina State University, who found that delays at intersections can be reduced by more than 25 percent by adding a “white” signal.
Instead of simply stopping or continuing, this signal would tell autonomous vehicles to find their own way across, while human drivers simply follow the car in front.
Co-author Dr Ali Hajbabaie said: ‘This will improve travel time, fuel consumption and safety for all cars on the road.’
Scientists have proposed adding a new traffic light color that uses autonomous vehicles to reduce traffic. When the light turns white, the autonomous cars determine the optimal flow and people just have to follow the car in front of them
The idea of a white signal rests on the assumption that one day a large number of vehicles on the road will be autonomous.
Because autonomous vehicles (AVs) can communicate with each other and the traffic infrastructure, they must be able to work together to create the most efficient traffic flow.
However, because AVs are still in their infancy, it is likely that a large number of vehicles will be driven by humans in the near future.
To ensure that both human and robot drivers can reach their destination quickly and safely, the researchers have proposed a fourth traffic light signal.
As it stands now, our trusty traffic light can only tell people to stop, get ready to go out or turn off the light.
According to this new system, as soon as the traffic light detects that there are enough AVs at the intersection, it switches to a white signal.
Dr. Hajbabaie says this “leverages the computing power of AVs to speed up traffic at intersections.”
The new system uses the computing power of autonomous vehicles. As this diagram shows, the cars communicate with each other and with the traffic lights to determine when to go
The autonomous cars figure out which lanes should be opened and lead ‘platoons’ or people through the intersection.
Once the light turns white, people simply follow the car in front of them, which is either an AV or another human who is also following an AV further down the group.
Because the system only turns on when there are enough AVs at the intersection, no person should ever be stuck at the front of a group while the white light is active.
Importantly, this system will only become more efficient as the number of AVs increases.
The concept of a fourth white signal is not entirely new and was proposed in 2020, but this study is the first to investigate whether this could work alongside zebra crossings.
Under the new system, pedestrians would normally cross the road following a red light/green light system.
The only difference is that, when the white light is active, the crosswalk would work as part of the autonomous vehicle network to produce the optimal flow.
Traffic simulations show that the new light color could reduce traffic by up to 25 percent when autonomous vehicles are widely deployed (stock image)
By simulating a four-way intersection, the researchers found that wait times could be reduced by 27 percent, even when pedestrians were taken into account.
This figure is calculated for a scenario of near-universal AV adoption, but Dr. Hajbabaie says there would still be “meaningful improvements” with lower AV adoption.
Dr. Hajbabaie says: ‘We found that when pedestrians are added to the mix, the white phase concept still improves traffic efficiency for everyone.
“And again, the higher the percentage of traffic that consists of AVs, the more efficiently traffic moves through intersections.”
This development would not only make travel faster, but also make cities less polluted.
Exposure to nitrogen dioxide, much of it from road transport, is believed to be the cause of 38,000 new cases of asthma in Britain and 240,000 in the US each year.
By reducing the time cars spend in traffic, cities can save drivers time and reduce air pollution in busy areas (file photo)
And research has shown that drivers inhale 40 percent more pollutants while at traffic lights.
By reducing the amount of time spent at traffic lights, cities can reduce emissions by reducing traffic congestion.
However, it’s unlikely that a fourth traffic light color will appear in your city anytime soon.
The researchers say they are aware that governments will not implement these technologies in the near future.
However, they say they are already taking steps to ensure future testing will be effective and safe.
Dr. Hajbabaie says the team has already created a physical model to test their theory, although the cars in this model are small enough to hold in your hands.
“This will help us identify implementation challenges without the costs (and safety risks) associated with using large-scale vehicles,” he added.
‘In the meantime, we are open to working with industry and research partners to explore ways to advance these technologies.’