The city of Sandy Springs has its own traffic management center.
The city of Sandy Springs has its own traffic management center.

A groundbreaking program that coordinates traffic signals in three Perimeter cities has been renewed for three more years. That will mean even better technology coming soon to tackle traffic jams, officials say.

But the Perimeter Traffic Operations Program renewal last week came only after one partner city, Sandy Springs, briefly balked over concerns it is doing more than its fair share and that police are still needed to direct traffic. Those concerns underscore how complex the traffic tech can be, and that it still has limits.

Officials in the PTOP partnership—Brookhaven, Dunwoody, Sandy Springs and the Perimeter Center Improvement Districts—say the state-funded program has slashed travel times since it began in 2012.

“It’s been a great program,” said Michael Smith, Dunwoody’s Public Works director.

“Although traffic volumes have increased in the three to four years of the program, traffic times have decreased. I think the first round of this program was a lot about getting the infrastructure in place…The next years will be about pushing the technology as far as we can.”

PTOP provides about $1 million a year in grant money to coordinate the timing on 99 Perimeter Center traffic lights: 55 in Sandy Springs, 33 in Dunwoody and 12 in Brookhaven. It costs the cities nothing, and PCIDs provides a traffic consultant that oversees the coordination.

Brad Edwards, Sandy Springs’ traffic and transportation director, told Sandy Springs City Council meeting that the goal is a system where “there’s not an ‘our side’ and ‘their side’” of Perimeter Center. In its latest PTOP report, from 2014, PCIDs said the average stopped-at-alight time on Perimeter Center streets has dropped 31 percent due to the program.

PCIDs claims the program saves commuters at least $9.8 million a year in time and gasoline that would otherwise be wasted, and that the program’s grant investment pays for itself every two days.

Those numbers may get even better as Sandy Springs moves forward with traffic signal upgrades next year. PTOP signals currently all use “time of day” technology, meaning programmed cycles estimated to be best for a given time of day, which traffic engineers can change remotely. The upgraded version will use sensors in the road to change timing based on traffic volume.

Sandy Spring is the oldest of the three cities and has the most modern traffic system, including a “traffic management center” where engineers can view various roads on a wall of monitors. Its underlying network of computer servers is still used to run the entire PTOP connections for all three cities.

The Sandy Springs City Council tapped the brakes on renewing PTOP at its Nov. 3 meeting, partly out of concerns that the other cities, especially Dunwoody, aren’t upgrading their own technology fast enough.

“They’re behind us three years or maybe more,” as a city that formed later, Edwards told the council in a report at its Nov. 17 meeting. But Dunwoody is now building its own traffic management center and extending fiber optics connections to all of its citywide signals. Smith said in an interview that upgraded signals will come after that network is completed to handle them.

PCIDs President and CEO Yvonne Williams said that with PTOP, new technology can easily plug into the existing collaboration. “As cities upgrade technology, it can be coordinated,” she said.

While Sandy Springs councilmen were largely satisfied and voted to renew PTOP, some suggested that their city and Dunwoody should share a traffic management center. Others said that’s inefficient, and Smith said it misunderstands how the PTOP network works.

“It already coordinates best as possible…The coordination is already done,” Smith said of the cables and digital systems that link the three cities’ Perimeter Center signals. In the digital age, a traffic management center is convenient, but not necessary to coordinate or tweak signals, he said.

“Our traffic engineer can be sitting at his house on his laptop and do everything you can do in a traffic management center,” Smith said.

The Sandy Springs council also was concerned that PCIDs continues to operate a separate program that hires police officers to direct traffic at major intersections and large companies’ parking decks.

Williams and Sandy Springs Police Chief Kenneth DeSimone said police are needed, not because of PTOP’s flaws, but because some drivers will always attempt to cheat or make mistakes and block intersections.

“People aren’t going to obey every traffic signal all the time,” Williams said.

John Ruch is an Atlanta-based journalist. Previously, he was Managing Editor of Reporter Newspapers.