Madison coordinating traffic signals, phasing out lagging left turns, in effort to ease congestion

MADISON – Trying to navigate your way through Madison can be frustrating at times, to say the least. As the city continues to grow, so does the congestion along the main arteries – causing what seems like never-ending traffic jams. Fortunately, some help is on the way.

Gary Chynoweth, Madison’s engineering director, said this week the city is changing how the timing operates on traffic signals through most of the City. The move is expected to help ease congestion along major intersections by coordinating the signals with each other.

“In the past, each signal was timed to handle the traffic flowing through it as a separate signal, independent from all other signals. Up to four different timings were set in each signal to accommodate the traffic demand at different times of the day,” Chynoweth explained. “Traffic flow through each signal may move with relative efficiency, but traffic could theoretically be stopped at each signal because they act as individual, unconnected signals.”

Chynoweth said the city has started to coordinate the signal timing to improve traffic flow along primary routes.

“The signals are programmed to start the green cycle in sequence that will improve the continuous flow of traffic along the primary route,” he said. “Unused side street or left turn time is added to the green light in the primary direction of travel and that green time will run full cycle regardless of gaps in traffic that would trigger a signal change in the old system. The green light is maintained to allow the passage of platoons of traffic being released from adjacent signals on the primary routes.”

The city has completed the signals on Countyline Road and are working on the signals on Hughes Road and Sullivan/Wall Triana. “We are monitoring the signals and making adjustments as appropriate,” Chynoweth added.

“In addition, we have several intersections in Madison where the left turn arrow for the side streets come on after the green light. The use of the lagging left saved time as independent signals but provide no benefit for coordinated signals,” Chynoweth also said. “All lagging left turns in the city will be phased out as the coordinated timing is implemented. Be aware of the changes and follow the new signal phasing.”