"Well, it is a little before evening rush hour," explains Tatum, the city's traffic engineer.
Tatum is sitting in the city's new Traffic Management Center keeping watch on an array of giant closed-circuit TV screens and computerized travel-time maps. The center, completed last September, is the most visible component of a $30 million-plus initiative that city officials say has already improved traffic and shaved precious minutes from commute times on several major routes.
Five years ago this month, the city began laying 120 miles of fiber-optic cable to connect traffic signals on such roads as Lamar, Winchester, Poplar, Airways, Summer, Germantown Parkway and Stage Road to a coordinated network. The synchronized signal system gives motorists — especially rush-hour commuters — a good chance of driving through several successive intersections without hitting a red light.
The system also enables city engineers to monitor and communicate with the signals, allowing them to tweak the timing of lights when traffic is especially heavy because of a sporting event or festival. To augment the system, closed-circuit cameras are being installed at more than two dozen intersections to give officials live images of traffic.
"The cool thing about the cameras is ... I can actually zoom in and out and pan in and out, tilt up and down," Tatum said, demonstrating his remote control of the equipment.
Taken together, the components give the city what is known as an Intelligent Transportation System. According to studies cited by the federal Department of Transportation, ITS technology offers cities and states relatively low-cost means to deal with traffic congestion and the increased air pollution it causes.
Simply synchronizing signals can produce $58 to $62 in benefits for every dollar spent on the systems, studies indicate.
The Memphis system is about 95 percent complete, Tatum said, with all the cable installed and engineers now able to remotely communicate with 407 intersections — more than half the city's signalized intersections. Under a separate $7.9 million Shelby County project, another 100-plus intersections will be connected.
Except for the camera installation, which was paid for from the city's capital-improvement program budget, the project was funded from grants through the federal Congestion Mitigation Air Quality program and the Surface Transportation Program.
Already, city officials are documenting improved traffic flow. Because the system picks up and tracks the Bluetooth signals emitted by motorists' mobile phones, engineers are able to monitor how long it takes a vehicle to travel from one intersection to another.
Comparing current travel times with those from before the system was synchronized, officials found that rush-hour commutes along Walnut Grove between Highland and White Station have been cut by 2-4 minutes, with eastbound traffic benefiting the most. Along Poplar, between East Parkway and Yates, travel times in both directions have been cut by an average of 2 minutes.
The improvement has been less pronounced on Germantown Parkway, from the Wolf River to Interstate 40. There, northbound and southbound travel times have been cut by one to one and a half minutes, or 5-10 percent, according to city officials.
The synchronization of signals helps whisk motorists through heavily traveled corridors much more quickly. The longer the corridor, however, the more likely it is that commuters will hit a red light at a "designed stopping point," Tatum said.
"It's not a magic bullet. Just because you have coordinated signal timing, it doesn't mean you're never going to have to stop ...," he said. "It's a tool to try to reduce delay and improve air quality."
©2016 The Commercial Appeal (Memphis, Tenn.) Distributed by Tribune Content Agency, LLC.
