Boston Transportation Department,
Red lines spread like veins across the dashboard filling the wall. The Central Artery, Storrow Drive, the Massachusetts Avenue interchange—there wasn’t a single stretch that wasn’t congested.
Deputy Director Allen propped his chin on his hand and glared at the screen.
“Another indicator’s broken its record.”
Jamie, the senior analyst, spoke to him with a troubled expression.
“Morning peak is over, but the PCI—Percent Congestion Index, the average congestion index—is still holding at 78. Why is this happening?”
Allen shook his head.
There were countless reasons.
The irregular urban layout, the pedestrian-first signal philosophy, the abysmal quality of the sluggish sensors, event variables…
But even taking all those factors into account, Allen felt helpless.
“Because I’m incompetent, I suppose.”
Jamie looked at Allen in surprise.
“Please don’t say that! This city has changed so much since you arrived, Deputy Director.”
Allen Smith, an MIT-trained traffic systems engineer, was one of the giants in the field.
Since his undergraduate days, he had drawn attention for his research mathematically analyzing human movement patterns, and in graduate school he earned his doctorate with an algorithm for dynamic signal optimization in irregular cities.
He worked at the MIT Urban Research Institute for ten years and participated in traffic AI projects in Singapore, Amsterdam, and Tokyo.
Allen’s papers were so highly regarded that they were referenced by leading institutions around the world, including the TRB—Transportation Research Board.
At one time, he was the talent IT companies and megacities most wanted to recruit. But Allen turned down every offer.
‘I have no intention of solving equations that have already been solved.’
That was also why he had left his post as chief engineer at the New York Department of Transportation and come to Boston.
Boston was pushing forward with a new project for a complete overhaul of its signal system, and to them, Allen was the best possible option.
“It did change a little.”
Allen recalled the past.
The city changed rapidly as soon as he took office.
The sensor database was standardized, and intersection signal logs were integrated in real time.
The BITN—Boston Intelligent Traffic Network—built under his leadership had once reduced the average downtown travel time by as much as 13 percent.
But that was a story of the past.
The screen was once again filled with red lines.
If a single hospital or a single new construction zone appeared, the system would be burdened in a chain reaction. As if the city refused his control and tried to return to its original rhythm.
In the end, the city had no choice but to go back to the previous system.
“Perhaps your ideals are too high, Deputy Director. To me, even now, it feels close to a miracle.”
“How long have you worked here?”
“A little over fifteen years.”
“The Transportation Department is an old organization. Everyone here must think like you. ‘Isn’t this good enough?’ they say.
When in truth, the entire city is screaming.”
He walked to the window and drew back the curtains.
Below the glass, Boston’s afternoon roads came into view.
‘Like the blood vessels of a patient dying of hyperlipidemia.’
He could see it.
Even if the blood flowed slowly, it would seem fine at first. But sluggish blood flow became the perfect environment for fat and waste to build up. Congestion became fixed in place.
“Is that why you gave the data to the MIT students?”
Allen turned around.
“It’s not as if they were asking for a budget. There’s no reason not to give it to them. What we need right now is a new perspective.”
In truth, that wasn’t the only reason.
When he received the report that MIT had requested the data, he suddenly thought back to his own undergraduate days.
The days when he wanted to read the enormous living organism called traffic through mathematics.
That passion had dulled with the years, and the man he was now had become used to efficiency and compromise.
Even so, he was grateful that someone was still asking the question, “Why does it get clogged?”
‘Yes, go ahead. If your undergraduate audacity finds a better answer than mine, I’ll gladly applaud you.’
It was the quiet encouragement of a researcher who had once believed he could change the world, sent to juniors who had not lost that belief.
* * *
The morning air was cold as ice.
Whoosh—
Taxis and buses occasionally swept past over the roads of the Longwood Medical Area.
Ellie and Jason had come out to the field from dawn again today to collect data.
“Ready?”
Jason carefully unfolded the drone’s wings.
Nod.
Tudududududu!
The wings rotated, kicking up a wind.
When Ellie tapped the touchpad, the drone rose into the air with a low hum.
“Satellite signal acquired! Raising altitude.”
The drone flew into the sky in an instant and illuminated the target.
“Vehicle occupancy rate, 92 percent. Queue length, 178 meters.”
A satisfied smile appeared on Ellie’s lips.
Collecting data was far harder than they had expected.
For days, Ellie and Jason had been going back and forth between the Transportation Department and the hospital district, gathering signal data and intersection footage.
But the hardest part was their confidence in the work.
“Seoha, do you really think we can understand all of Boston’s traffic with this data?”
Ellie’s gaze moved over the numbers on the laptop screen.
The data they had collected was only the tip of the iceberg when compared to the entire city—at most, just a few percent of the total traffic volume.
But Seoha answered calmly, as if there were no problem at all.
“We have the data from the Transportation Department. If we accurately read the patterns in the key sections, we can restore the rest by comparing it against that data.”
Ellie shook her head. In her opinion, the data was hopelessly insufficient.
“Is that really possible?”
“The source data is a little lacking, but it’s not impossible.”
Instead of explaining, Seoha showed her the laptop screen.
“We’ll extract only the signal patterns from the camera footage and combine them with the congestion information and traffic volume data we received from the Transportation Department.”
Seoha’s hands moved quickly over the keyboard.
“If we organize the phase by time period and calculate the average delay values, we can predict the flow in sections we can’t see. In the end, all traffic flow is one connected equation.”
Jason laughed in admiration.
“Is this a movie? Sounds like magic that comes true as soon as you say it.”
Ellie bit her lip.
“All right. You’re serious, aren’t you? Then we’ll do our best too.”
Ellie didn’t want to remain a mere spectator on this team.
After hearing Seoha’s plan, she went around campus laboratories and borrowed all kinds of cameras, drones, and scanners.
Jason had a talent for handling machines.
He corrected errors by cross-validating information obtained from LiDAR—a distance-measuring device using light—with thermal imaging cameras. Adjusting the drone’s altitude, GPS errors, and sensor response speed was also his job.
In that way, the two were able to collect far more extensive and higher-quality data than Seoha had expected.
* * *
At last, all the data had been gathered.
On the screen covering the study room wall, Boston’s main road network had been recreated in precise detail.
Jason said as he organized the cables.
“Field data input complete.”
Seoha sat down in front of the monitor and moved his hands.
The LiDAR point cloud, the footage collected by drones and cameras, and the various information received from the Transportation Department merged one by one.
Millions of datasets were aligned into one under the algorithm Seoha had created. Then the city’s overall traffic flow appeared.
Ellie caught her breath.
“Is this the real-time situation right now?”
Seoha nodded.
“It’s a virtual simulation extracted from data, though. But the margin of error probably won’t be large. It’s about time for the evening commute congestion to start, so let’s check.”
When Seoha entered the code, the screen responded immediately.
The gray road network was divided into red, yellow, and green according to congestion conditions.
“I-I’ll check the current traffic situation.”
Jason opened a navigation app and compared the current traffic conditions with the program.
“Wow!”
“It’s almost identical.”
With the given data, Seoha had recreated the traffic with almost no error.
“The data was that good.”
Seoha raised his thumbs toward the two of them.
“Now we can start the assignment.
Let’s think together about how to create the most optimal traffic flow.”
The meetings continued for days.
When class ended, the three of them naturally gathered in one place and opened their laptops.
During breaks, at cafés; at night, in the campus lounge study room. Equations piled up on the table.
Seoha could have completed everything by himself, but he did not.
He wanted this project to remain an achievement they had all accomplished together.
“We probably won’t be able to apply the optimization plan we create in the field. Outsiders can’t know all the variables of reality.
Still, I think it’s meaningful if we can at least convey the message that ‘there is this way of looking at it.’”
The two nodded as if they agreed.
Seoha picked up a pen and wrote several equations on the board.
“What we have to do is simple.
Mathematically classify the causes of the bottlenecks, calculate the phase differences between intersections, and derive an optimization scenario.”
Once the work was defined, the pace accelerated.
Ellie took charge of cleaning the collected data and removing outliers. Jason estimated the queue lengths at each intersection node and built a graph network, while Seoha gathered all those results, adjusted the algorithm, and completed the optimization model.
And a few days later, the results finally came out.
* * *
Allen stood for a long while in front of MIT’s main entrance.
It had been a long time since he had visited the campus.
“Since I’m here anyway, I might as well go.”
The place he headed was Building 2, the mathematics department building.
After confirming Whitman’s name on the lecture room list, Allen let out a faint laugh.
“Looks like he’s still going strong.”
He had also been Allen’s teacher.
The reason Allen had been able to make a name for himself as an urban engineer was because of the mathematical thinking he had learned under the professor in graduate school.
He looked into the lecture room from outside the door for a moment, then quietly opened it and entered.
Allen extended his hand to Whitman.
“I heard the team the Transportation Department provided data to is presenting today.”
“You came at the right time. It’ll be interesting.”
He offered Allen a seat in the front.
The lights in the lecture room went out, and Boston’s road network appeared on the projector screen.
Allen’s gaze turned to the Asian boy.
‘That child must be the project leader.’
He could tell just from the way he moved.
At the boy’s instructions, the team members adjusted the equipment.
“Hello. I’m Yu Seoha.
Our team questioned whether Boston’s traffic conditions, infamous throughout the world, truly cannot be improved. Using the real-world data we were given, we attempted to reproduce the current traffic situation.”
When he nodded, colors began to appear on the roads.
Like a time-lapse, the roads on the screen changed rapidly.
Red spread through the downtown area, yellow bands expanded around it, then gradually faded into green.
As if the hands of a clock were spinning rapidly, a day in Boston flowed before their eyes in compressed form.
‘They extracted this from that meager amount of data?’
To him, the deputy director, it was an all-too-familiar sight—but it was also confidential information outsiders could never know.
“In conclusion, Boston’s signal system is optimized only at the level of individual intersections. This may be efficient locally, but from the perspective of the overall system, it creates bottlenecks.”
He wrote several equations on the board.
The city’s flow appeared as differential equations.
Allen fell into thought as he looked at the screen.
‘It hurts to have it pointed out from the outside.’
To change signal cycles, they had to obtain approval from the traffic systems committee, and because budgets differed by district, even installing a single sensor required consultation.
Civic groups advocated pedestrian priority, while the routes of police, firefighters, and emergency vehicles also had to be secured.
So of course the system had become a complete mess.
Even so, Allen wanted to push through the ideal.
How satisfying would it be to cleanly straighten out the traffic of this filthy city? He still thought about it every day.
“There is a solution.”
Seoha began writing equations on the blackboard.
The formula that began in one corner spread across the entire board. Allen watched it, forgetting even to breathe.
“What we propose is a phase synchronization model.
If the entire network is controlled with this algorithm, perhaps this city’s notoriety can disappear someday.”
Snap!
At Seoha’s signal, the algorithm was applied to the roads on the screen.
The red color of the downtown area gradually faded, turning yellow and then green.
As the signals of the entire city came under the control of a single algorithm, the traffic network, which had been like clogged blood vessels, began to breathe.
Seoha pointed to the graph with his finger.
“This is not a simple simulation.
Based on Boston’s real-time data, when compared to actual traffic flow, the error rate is only 2.9 percent. In other words, it is a sufficiently feasible scenario.”
At last, every road in Boston turned green.
Allen felt his chest swell.
‘Adult circumstances? The mayor’s sponsor districts? The interests of organizations?
What does any of that matter? If you’re an urban engineer, you ought to dream like them!’
That boy had created such a precise algorithm from data as ragged as rags.
If he were given the real data held by the Transportation Department, just how far could he go?
Allen’s heart began to pound fiercely.
Clap, clap, clap!
The presentation ended, and the lights came on.
What the students saw was a middle-aged man rising with a moved expression and applauding passionately.