News-Record.com

GREENSBORO -- When Joe Mullinax started working for the city of Greensboro in 1978, the computer system that coordinates hundreds of local traffic lights filled two rooms at City Hal

Now the signal-network manager works with a system small enough to fit inside a broom closet.

And the new one that Greensboro is about to install will have even less hardware.

But don’t confuse shrinking size with any loss of complexity or significance: The replacement will take nearly four years to install, cost up to $24 million and allow the city to synchronize traffic lights farther out in suburbia.

“We’re going to be able to reach out and get some of these fringe areas that we can’t get right now,” Mullinax said. “People don’t always realize how crucial this system is. If I turned it off, I guarantee that you’d notice.”

The system saves money for Greensboro motorists with increased fuel economy, keeping them moving rather than wasting fuel idling at one traffic light after another. It also cuts air pollution caused by traffic tie-ups.

The state Board of Transportation recently approved a $16.8 million contract covering part of the new system’s cost. The project should get under way later this summer.

The existing system is 16 years old and works reasonably well controlling traffic at 386 intersections across the city, Mullinax said.

But it shows signs of age stemming from its heavy use of “twisted copper” wiring, which is prone to occasional interruptions caused by temperature extremes, lightning strikes and blips in the power grid.

The new network will use fiber-optic technology, coordinate more than 450 intersections, provide greater video surveillance of major crossroads and be less vulnerable to such disruptions as lightning strikes, Mullinax said.

It will cost $4.5 million in local money to install the new technology. The city will pay $3 million from previously approved bonds, then add another $1.5 million for extra capacity so other municipal departments can use the system, said Adam Fischer, acting director of transportation.

The remainder will be paid from a combination of state and federal sources.

The current system relies on sensors embedded in the pavement at various intersections to gauge traffic volume and to help determine how much “green time” each direction gets.

The system is timed so that once motorists have stopped at one traffic light on a major street, they should have a string of continuing green lights — if they travel at or slightly below the posted speed limit.

All bets are off if you go too fast, turn onto another street or drive through an area where intersections were built too close together for proper synchronization.

Most breakdowns in the system go undetected by motorists, Mullinax said. Each traffic signal has backup equipment that fixes the glitch automatically or keeps the light working at its proper pace until technicians can make repairs.

Mullinax hears from drivers when they detect a breakdown or believe they have spotted a design flaw.

“I talk to happy people occasionally, but not too often,” he said. “I fully understand when people complain. I mean, I drive, too.”

The current system isn’t perfect, nor will the new one be, but both are a huge improvement over an uncontrolled traffic grid, Mullinax said.

Greensboro was on the cutting edge when it installed its first citywide signal-control system in 1974, he said. Nowadays, nearly all larger communities have similar technology in place to keep traffic moving.

The technique has important environmental benefits, said Lorelei Elkins, regional coordinator of the Triad Air Awareness program.

“When a car is sitting in idle, whether it’s in a fast-food line or at a traffic light, you’re wasting fuel,” Elkins said. “And every time you waste fuel, that means there are more unnecessary emissions coming out of your tailpipe.”

One of the new system’s key attributes is its elimination of the small computers at each traffic light that gather information, then relay it to the central processor downtown, Mullinax said.

Instead, each traffic light will communicate directly with the nerve center at City Hall, bypassing a step where glitches can occur, he said.

Still, even the current system is impressive. From his computer, Mullinax can check maps showing big chunks of the municipal grid or one that depicts the entire city, giving up-to-the-second information about how traffic is moving at each intersection.

Hunched over his terminal one recent morning, Mullinax surveyed the map and saw a problem at only one of the 386 intersections, East Wendover and Sykes avenues.

“Maximum green time error,” he said.

Something caused the sensor in a left-turn bay to keep the signal lit too long in that direction. Oncoming traffic headed straight through on Wendover backed up at a red light, facing an empty turn lane that still had a green arrow.

“It’s not a huge problem, but it is definitely irritating to the other (oncoming) motorists,” Mullinax said.

Before he could alert technicians to the problem, the traffic light’s on-board computer diagnosed and fixed it. But he said the problem would probably require hands-on repair at some point.

That’s just one of the realities in dealing with outdated equipment, Mullinax said.

But Greensboro motorists should be pleased to know that help is on the way.

Contact Taft Wireback at 373-7100 or taft. wireback@news-record.com