The Art of the Stoplight Sync: Meet the Team Turning All of Austin's Red Lights Green

Feb 17, 2016

A few weeks ago we asked you to tell us what you want to know about Austin. It’s a project we’re calling ATXplained. You sent in dozens of questions you wanted us to investigate. We narrowed it down to one by letting the public vote at KUT.org. The story those voters chose is about traffic light synchronization, and when all of Austin’s lights will be synchronized.

KUT’s Audrey McGlinchy looked into it.

Picture it: You're idling at a red light, and it feels like it's taking forever. It seems like other drivers are getting all the green — why can’t you have some? Or, maybe you’re not at a red light. Maybe you’re one of the lucky ones, hitting only green after green.

When a consecutive series of stoplights are perfectly timed so that you can simply fly through green lights all along your route. It's almost a spiritual experience; you could say it feels like someone’s wrenched open the gate to commuter heaven.

'Powerful but responsible'

I’m not suggesting you think of Jonathan Lammert as some sort of god, but he does feel powerful at times.

"Powerful — but responsible,” he says.

Lammert works as a signal engineer with the City of Austin. Out on the corner of Seventh Street and Shady Lane, he peers into the innards of a traffic signal control box. Whatever he's just done in there made the light at Shady turn green, 25 seconds earlier than it did the time before. Every day, Lammert drives roads where the traffic lights are synchronized, and, if he feels it necessary, he’ll tweak the timing of the lights so that drivers hit that sea of green as often as possible. He has that power.

On a recent Thursday afternoon, driving the stretch of Seventh Street between I-35 and Shady Lane, Lammert speaks aloud his calculations as he thinks them through.

“Since Springdale was green well before we got there, if we want to make Shady go green earlier by like 20 to 25 seconds, then we could get through Springdale just as it turns green, and then we could get through Pleasant Valley when it’s still green," says Lammert. "So that’s one thing that we’ll keep in mind.”

What he’s getting at is that a single traffic signal is not an island: If you change the timing of one, it affects the others. So after he finishes up the light at Shady Lane, he calls someone who can tweak the timing of the lights remotely and asks that Springdale get the same adjustment.

'I don't see why these lights can't'

"Maybe I’m missing something, but I think there’s opportunity for improvement in Austin traffic lights,” David Kobierowski says. He's the one who submitted the winning question for the second round of our ATXplained series:

“When will Austin’s traffic lights be synchronized?”

“You have to time the shifting of your car, your lane change, everything, so fast, and you have to be the first one out of the gate," Kobierowski says. "That’s the way you get to the next light before turning red. When the first light turns green, then the second one should turn green, maybe a couple seconds later.”

Kobierowski drives a car with a manual transmission.

At the Airport Boulevard exit off I-35 South, there's a set of lights that frustrates him, starting with the left turn onto Airport. 

“This one is green, and this one’s red,” he points out.

The cars stopped at the red light are almost backed up to the green light.

"I don’t see why these lights can’t be synchronized, so that as soon as that light turns green, instead of this one turning red, it turns green.”

There's an art to it

"Right now we have about 85 percent of our signals are synchronized, and we have about 1,000 signals in the city," says Jim Dale, the assistant director of Austin’s transportation department.

“We may not need to hit 100 percent, because some of those signals are so far removed from other intersections that if we just let them what we call 'run' — instead of synchronized — 'run free,' it can provide a better level of service or better reduce, minimize delay for travelers, if we just run it isolated.”

Dale explains that if you have one light two miles from the next, it’s hard to predict what will happen in those two miles. So it doesn’t make sense to pre-set the lights. Plus, the roughly 850 lights that are already synchronized keep the department busy enough. It’s the work Jonathan Lammert does – going around, driving the roads, re-timing the lights.

“We’re striving to re-time one-third of the signals every year; that’s the national best practice," says Dale. "This year we’ll time 200; it’s about 20 percent.”

Dale says the department’s hiring another signal engineer so they can hit that goal of re-timing one-third of the city's synchronized lights next year. The city’s also looking at new technology that would do the work of a signal engineer – feeling out the patterns of drivers and automatically re-timing lights. It’s called adaptive signal control. But, says Dale, while it does the work of a human, it doesn’t remove the need for one.

“Some of our traffic, there’s a little bit of chaos to it as well," says Dale. "All of us have, when we’re driving, we have different behaviors in how we decide to drive. There’s just so many things happening.”

“There is an art to it," says Kevin Balke, a researcher with the Texas A&M Transportation Institute. "There are people that can do it much better than others.”

Balke says you could think of signal engineers as artists, rather than scientists or mathematicians:

“They have that feel for the way traffic flows up and down the roadway. It is very tempting to look at the numbers and plug the numbers in. But the numbers only get you that starting point. The way you really get a system working at its optimum is to drive up and down the roadway.”

Then, there’s the future

Going back to Jonathan Lammert, after he just changed the signal at Shady Lane — remember how he immediately called in that change for the next light at Springdale?

The man he called to make that change was Kenny Moses, a traffic system technician in the City of Austin's Traffic Management Center.

To say Moses is surrounded by screens would be an understatement. He’s got three at his desk, plus, if my count’s right, 14 on the wall in front of them. These screens show intersections throughout Austin – Cesar Chavez and South First, Guadalupe and Dean Keeton. In other words, Moses’ job is to stare at and respond to Austin traffic. (Wave to him if you’re so inclined.) And what Moses loves about his job is what most people hate about the nature of traveling by car:

“It’s something different every day. It doesn’t get boring. There’s always something else going on.”

Moses, like all the others who work on Austin's streetlights, talks of the limits of light synchronization. While it has the power to move traffic along, it can’t increase capacity on the road.

“Even though you get more green time there, if we don’t make changes down the road, you’re going to catch the red there, and what you’re doing is just moving the traffic jam from point A to point B.”

Then, there’s the future of traffic lights — right now, there are cars on the market that communicate with one another. These traffic engineers all say they see in the future a world without the need for traffic lights – a world in which cars tell each other to stop or to go. As for Moses, though, he says he’s not worried about his job — traffic will always require a human at its helm.

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