Engineer Calls the Signals in High-Tech Traffic Plan

Toan Nguyen could be called Ventura’s traffic guru--a benevolent dictator who decides how much time city residents spend getting to and from work.

From his desk, the Ventura traffic engineer can see your car, every stoplight and a grid that tells him exactly how long you spend sitting at an intersection.

Using powerful computers and integrated systems, traffic engineers like Nguyen, in every city in the county, have minimized the mayhem of residents’ daily commute. They keep a watchful eye on every intersection and constantly tinker with the smallest of variables--such as how many hundredths of a second elapse between a yellow and red light.

For Nguyen, the intricacies of traffic management are a passion, and he has spent countless hours fine-tuning Ventura’s programs. Traffic engineers in other cities, from Oxnard to Simi Valley, say Ventura’s state-of-the-art equipment combined with Nguyen’s efficient and cost-effective operation make Ventura’s setup the most advanced in the county. Other cities, not surprisingly, hope to use it as a guide when upgrading their own systems.

Ventura’s system is different because the city uses cameras at some intersections to monitor traffic flow, in addition to magnetic loops buried in the ground that trigger a light to change. Nguyen also is able to fix some problems from his computer at City Hall instead of sending out a maintenance worker, a feature that saves time and money.

Nguyen has Ventura’s 130 intersections set up like this:

All the lights in an intersection will go from red to yellow to green in a cycle of 110 seconds. Nguyen, however, can vary this cycle at a particular signal if it will allow traffic to flow more smoothly. For example, based on the historical traffic flow at a particular intersection, Nguyen can lengthen the time that a signal remains red in one direction in order to lengthen the time the signal is green in another direction.

Nguyen looks at each intersection as a pie--if a few seconds are given to one light, they have to be taken from another.

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From his desk he looks at three computer and video screens. On one, he can flip back and forth to show views of traffic at seven different signals around town. Another shows a layout of the whole city with blinking lights that indicate whether or not the signals are working. On the third screen, he can call up an animated image of every intersection, complete with real-time data of waiting cars and empty lanes.

In addition to the cameras, Nguyen relies on signals transmitted to his computer by hundreds of magnetic “loops,” or large wire circles in the pavement that detect cars.

Traffic flow also is managed by having different signals follow different schedules, depending on the time of day. In Ventura, a signal’s schedule changes five times during a weekday and three times on weekends.

On a recent day, Nguyen was busy resetting vehicle-detection zones that were out-of-date because the Victoria Boulevard interchange had been completed. He spotted one nearby street in which the view from the camera was out of place. He was able to fix it by changing the camera’s viewpoint with a click of the mouse on his computer.

Without the adjustment, a car might have gone undetected and waited longer than necessary for a green light.

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“It’s quicker, but also safer for me to adjust from here, instead of setting up cones and blocking off part of the road and adjusting it from the box out there on the street,” Nguyen said.

Nguyen, 40, moved to Kansas from Vietnam when he was 13. He never thought of traffic management as a career, intending to use a degree in civil engineering to build high-rises.

But after coming to Ventura a decade ago, Nguyen entered the world of traffic.

“At that time, it was the only place I could find a job,” he said. “But I’ve found my niche. This is a job where I can work with computer software and engineering.”

He said computing used to be his hobby, so combining it with his profession was a perfect match.

“Now I love it,” he said from inside an office filled with maps, rulers and diagrams.

The system that Nguyen uses has potential--and thus far, untapped--benefits. For example, it’s possible for Nguyen to keep data on how many motorists run red lights. Or he has the capability of allowing the police and fire departments, or even public buses, to override red lights from their vehicles when they need to. But the decision to use the system in these ways are not his to make, the traffic engineer said.

Residents often contact Nguyen with complaints, which according to Nguyen is usually the quickest way to determine if there’s a problem at a particular intersection. The most common complaint, he said, is from pedestrians who feel the walk light does not last long enough.

If a pedestrian calls to complain, Nguyen clicks on the intersection and watches it run through a cycle to make sure the lights are on schedule. If need be, he sends a technician out to time how long it takes to cross the street.

“If it’s not enough time, then I just increase the walk time,” he said. “But then [another light] has time taken away.”

Ventura’s traffic monitoring system is similar to others across the county. However, Nguyen has customized Ventura’s programs, making them easy for maintenance workers to use. Many other cities cannot make as many changes to signals directly from City Hall.

When a stoplight malfunctions in Ventura, a maintenance worker is automatically paged with the location and nature of the problem. Cameras malfunction less frequently than ground monitors and are less expensive to maintain.

“We learned a lot from Ventura, because their system is state of the art and Toan has it hard-wired to City Hall,” said Bill Golubics, a traffic engineer in Simi Valley.

Simi Valley’s system mainly operates using loops. Golubics said the system works well but is expensive to maintain.

John Helliwell, traffic manager in Thousand Oaks, agreed. “The disadvantages of the loops are that they have to be reinstalled every time they’re destroyed--sometimes the detectors malfunction or the wires will break or water will get in pavement.”

Helliwell said Thousand Oaks plans to install some cameras next year.

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In Thousand Oaks, like other cities, all traffic lights are synchronized. “If you travel at the posted speed limit and you get a green, you should be able to hit green lights the whole way,” Helliwell said. “I sometimes get 15 in a row.”

Although the cameras, the synchronization and the loops work together to create an integrated system, Nguyen said he has noticed an increase in traffic and congestion on Ventura’s streets that no amount of planning can alleviate.

“We try to be proactive and change the timing before we get complaints,” he said. “People don’t mind waiting at major intersections. But the sacrifice is for the people on the side streets who might have to wait almost two minutes.”