For the first time in nearly 30 years, the City of Minneapolis is fine-tuning all of the roughly 800 traffic lights throughout the city.
By counting traffic and adjusting the timing of the lights accordingly, the city expects drivers will see a 10 to 15 percent reduction in delays and a significant reduction in gas emissions once the project is complete in late 2013.
“We’ve adjusted small parts of the city here and there, but this is a very large undertaking for us,” said Nick VanGunst, a professional traffic operations engineer for the City of Minneapolis Traffic and Parking Services Division.
The retiming process has already started in downtown Minneapolis and will finish sometime in the summer, VanGunst said.
About 600 of the signals in the city are programmed to fixed time schedules based on traffic counts from the city. Signals give priority to routes that are more heavily trafficked — lights on main routes will stay green longer than their cross streets. During peak drive times, the timing of the lights is extended so traffic can flow.
These lights continuously run on their preset schedules and can’t detect if cars are waiting.
Traffic signals around the University of Minnesota are actuated, which means they can detect vehicles and adjust timing independently.
VanGunst said ideally Traffic and Parking Services would like to retime at least a quarter of the city’s lights every four to five years. A lack of funding has made that impossible in recent years and has caused many of the lights in the city to fall out of sync.
“Signal timing is one of those things where it’s good to do but from a priority standpoint, it ranks pretty low,” VanGunst said. “It’s usually the first thing out the door.”
In addition to the signal adjustments, the City Council approved a purchase Friday for a $160,000 upgrade to the traffic signals operating system software.
Known as TACTICS, the new software is necessary for traffic to flow efficiently with the Central Corridor light rail.
It also has the ability to give priority to mass transit vehicles. The new system can detect if a bus is running behind schedule and prioritize its timing schedule for the delayed bus.
“It’s basically a $160,000 CD that will be handed to us,” VanGunst said. “It’s like buying Microsoft Office 2011 to upgrade from Microsoft Office 2003.”
The Metropolitan Council covered $130,000 of the software upgrade cost.
But the total cost to install the new system will be closer to $5 million because Traffic and Parking Services will have to update many of its traffic signals in the city to be compatible with TACTICS, VanGunst said.
The upgraded system will eventually replace the old signal system that has been in place since the ’70s.
Allan Klugman, a traffic engineer with Traffic and Parking Services, said the new TACTICS system will have better traffic management and timing control than the old system.
“When you coordinate lights, the biggest thing isn’t just that they turn green, yellow, red, but it’s that they do it in a timed pattern,” Klugman said.
For the majority of traffic lights in Minneapolis, timing is everything. That was proven in early October when a power outage knocked out the traffic signals’ central computer.
The outage caused signals to work out of sync, which caused significant and noticeable delays, Klugman said. The signals resumed their normal timing last Monday.
Sandy Colvin Roy, a Minneapolis city councilwoman, said the new TACTICS software is essential for efficient traffic flow along the light rail.
She said the current signal system “can be incredibly frustrating,” especially along the Hiawatha light-rail line.
Because they don’t need to be updated, the traffic signals around the University will be the first around the city to be upgraded to the TACTICS system.
By the end of 2013, the city hopes to have every signal retimed and running on the new software.