By Amy Wenk
Not long ago, if a traffic engineer wanted to adjust the timing of a traffic light in Sandy Springs, he had to sit on the side of the road and count the cars going past.
“You actually had to go out to each intersection and you would sit there and try to time it,” said Traffic Services Manager Chris Waters. It took a week to adjust four or five signals, he said.
Now, thanks to fiberoptics and computers, it’s all done automatically from a monitor-filled, access-controlled office hidden in Sandy Springs City Hall called the Traffic Management Center (TMC). Since construction began in June 2008, the city has invested $1.4 million in traffic cameras, fiberoptic cables and related technology for the TMC.
Waters can change every light in the system without leaving his desk.
With the TMC, “we can put an entire corridor up on the screen” to see how one signal change impacts several intersections, Waters said. “It’s basically enabled us to do this quicker and more efficiently in here … as opposed to being out in the field.”
Now it takes only a couple of days to adjust the timing of all the signals on Roswell Road, said Waters.
City officials say it is working.
Traffic has improved on Roswell Road, according to an independent study by Geostats. In 2009 citizens saved $1.4 million in time and fuel over 2008.
In 2009, motorists traveling northbound on Roswell Road (from Wieuca Road to Dunwoody Place) saw reductions in travel times, number of stops and stop time during both morning and evening peak commutes, as did drivers traveling the same route southbound during the morning rush.
With additional cameras coming online in the next year and new programs in the works, the TMC is primed to further reduce travel times for Sandy Springs residents.
The center currently controls 18 cameras along Roswell Road that capture real-time images of traffic flow from the north, south, east and west.
Waters said when the system is completed, there will be a total of 70 traffic cameras installed throughout the city.
“We are looking at having cameras in key locations,” Waters said.
Two more cameras would be installed on Roswell Road. Others would be placed on Peachtree-Dunwoody Road, Abernathy Road, Dunwoody Place, Hammond Drive, Northside and New Northside drives, and other arterials and collectors.
“When it is over and done with, we basically will have coverage of about 90 percent of our traffic signals,” Waters said.
His hope for the next calendar year is to be 60 to 70 percent built out.
In the next two weeks, Waters intends to install four cameras on Dunwoody Place. Waters said he plans to install 18 cameras into the Perimeter Community Improvement District (CID) area in the next month or two.
Another project Sandy Springs will soon embark on is the Advanced Transportation Management System (ATMS) along Ga. 9 with the cities of Roswell and Alpharetta, as well as the state Department of Transportation. The ATMS project will improve operations along Roswell Road and allow traffic communications between the cities, Waters said.
The data collected at traffic intersections is sent to the TMC via fiber-optic cable. Field switches, funded by an $856,000 state transportation grant, are the communication link that transmits the electronic data.
Waters and other staffers monitor the streaming video in the TMC on six screens — two 90-inch, rear-projection screens and four 42-inch liquid-crystal-display screens — that display the live camera feed from Roswell Road. Staffers sit at a desk with two computers and a telephone.
TMC staff typically makes quarterly adjustments to the timing of the signals. But when large-scale accidents occur on I-285 or Ga. 400, staff members can make real-time adjustments to ease the congestion.
TMC staff also can utilize state-licensed software to monitor 24 traffic signals along Roswell Road.
“We can pull that up and see what is actually taking place inside our signal cabinet,” Waters said.
“One of the really nice things with this is anywhere I can get an Internet connection, I have access to my signal database, as well as the cameras. That has actually saved us a lot of after-hours calls.”