ABOVE: A screenshot from a MnDOT camera showing a fish eye view of the intersection at Blue Earth Avenue in Fairmont.

FAIRMONT– The Minnesota Department of Transportation (MnDOT) last month replaced antiquated traffic detection camera systems at all of the traffic signals on Highway 15 in Fairmont, with the exception of Goemann Road. The cameras bring with them not only simplification but also added benefits.

Scott Thompson, a traffic engineer for MnDOT out of District 7, said that the new detection systems use just one camera per intersection, as opposed to the four cameras that the old system used. Five new cameras were installed in December at five different intersections.

“The one camera detects all of the various movements at the intersection. It’s a huge benefit from a maintenance perspective. With one camera there’s less to clean and take care of and maintain,” Thompson explained.

As for the purpose of the cameras, Thompson said in the beginning traffic signals were all timed and each indication only got a set amount of time. Over time, new detection systems were created to operate more efficiently so that someone wouldn’t come up to a red light and sit with no traffic.

“The typical technology that was used for actuation was metal loops in the pavement… and when a vehicle pulled up, the metal mass would disturb the current going through the loop in the pavement that would send a signal to the traffic signal controller that a vehicle was waiting so that it would get a green indication,” Thompson said.

At the time those were used, Thompson said it was an advancement because it resulted in significant decreases in delays at intersections. However, there were some issues because loops couldn’t be easily installed and maintained in the pavement.

“If we had a relatively new road pavement and we were putting in a traffic signal after the fact, we wouldn’t want to rip up the pavement to put in loops so we would cut loops in to provide detection capabilities,” Thompson explained. “But because we live in Minnesota with freeze-thaw cycles, it would cause expansion and contraction and ultimately sever the wires used for the loops.”

Within the last 30 years or so, Thompson said camera detection started to be used.

“The cameras look at the intersection, close to where vehicles should be stopping and waiting at a red light. They sense a change in contrast,” Thompson explained.

Instead of a loop, the cameras tell the traffic signal a vehicle is waiting so that the light changes color.

Thompson said the new cameras that were just installed have more capabilities and an added bonus is that they can count vehicles.

“It’s incredibly critical for our work because if we know how many people are turning left and how many are going straight, we can adjust the time given to those movements to make sure that one movement isn’t experiencing a cycle failure,” Thompson said.

He said they can also time and coordinate all of the signals along the corridor together so that if you’re on Highway 15 you can get a ‘green wave’ and sail through without having to stop at multiple signals along the way.

Thompson stressed that the cameras cannot see into vehicles, nor can they read license plates. They also do not record.

“They’re purely used to send signals to the signal controller telling them when it’s time to provide green lights,” he said.

Josh Kraus of MnDOT, who specializes in signals and lighting, said that District 7 as a whole has been moving to the ‘fish eye’ style cameras because they have more capabilities and perform better than the four camera system.

Within District 7’s 13 county area, there are 47 traffic signals and the goal is to get all of them that don’t have good loops in the pavement using the new camera system.

“We have 19 new cameras now,” Kraus said.

He said the cost comparison between the four camera system and new one camera system is basically the same but reiterated that the maintenance will be easier.

“There’s a lot less wire in case of rodents or faulty connections. There’s a lot less that can go wrong with the new ones,” Kraus said.

Thompson added that despite the best efforts to mouse-proof the traffic signals and lighting systems, rodents do get into them and can gnaw on wires.

“We have a constant battle of trying to keep them rodent-free. Sometimes when you see a signal flashing red, especially in the winter, it’s because we’ve had mice in there chewing on wires and causing chaos,” he said.

The new camera systems had no cost to Fairmont or Martin County, rather Thompson said MnDOT picked up the cost for them.

All in all, MnDOT is excited about the new camera systems.

“It’s really improved how we can improve our customers with regard to reducing delays and making sure that they are getting the green lights that they need,” Thompson said.