Gridlock Guy: Intelligent left turns are decreasing wrecks in one Gwinnett city

March 28, 2022 Atlanta: A fatal crash involving a motorcycle caused delays on Moreland Avenue in DeKalb County on Monday morning, March 28, 2022. At one point all southbound lanes were shut down while authorities investigated the crash at South River Industrial Boulevard, according to the Georgia Department of Transportation. The wreck was reported just after 7:30 a.m. and was cleared by just after 9 a.m. Investigators believe a driver turned left in front of the motorcycle, causing the bike to crash and killing its rider, according to DeKalb police. The motorcyclist was not identified. Charges are pending for the driver of the car, who also has not been identified, police said. Moreland Avenue was shut down while the man’s body was removed by the DeKalb County Medical Examiner’s Office. His crumpled motorcycle could be seen lying in the southbound lanes. (John Spink / John.Spink@ajc.com)

Credit: JOHN SPINK / AJC

Credit: JOHN SPINK / AJC

March 28, 2022 Atlanta: A fatal crash involving a motorcycle caused delays on Moreland Avenue in DeKalb County on Monday morning, March 28, 2022. At one point all southbound lanes were shut down while authorities investigated the crash at South River Industrial Boulevard, according to the Georgia Department of Transportation. The wreck was reported just after 7:30 a.m. and was cleared by just after 9 a.m. Investigators believe a driver turned left in front of the motorcycle, causing the bike to crash and killing its rider, according to DeKalb police. The motorcyclist was not identified. Charges are pending for the driver of the car, who also has not been identified, police said. Moreland Avenue was shut down while the man’s body was removed by the DeKalb County Medical Examiner’s Office. His crumpled motorcycle could be seen lying in the southbound lanes. (John Spink / John.Spink@ajc.com)

Left turns are necessary, but they are also one of the most dangerous routine things that drivers do. The latest innovation from a local smart traffic technology firm is looking to make these maneuvers safer and more sensible. They have deployed intelligent left-turn technology in Peachtree Corners, and the results, so far, have been sizable.

“You pull into a pocket, which is that little place on the side of the road where you wait for the opposing traffic. You see a gap in the opposing traffic coming 70 miles per hour towards you, you move across and drive into the subdivision or parking lot or wherever it is. If all goes well, great stuff. If all goes badly — a huge crash — because of the high speeds of the approaching vehicles,” Applied Information president Bryan Mulligan explained to the AJC and 95.5 WSB.

“(The intelligent left turn) uses a detector to pick up the trajectory of the cars that are approaching and provides you information — flashing lights — when it is unsafe to go across.”

Mulligan’s mantra is relatable: traffic systems have remained largely unchanged for a century, and simple nudges and tweaks can make the roads much safer and more efficient.

Mulligan’s Applied Information and tech incubator iATL, based in Alpharetta, partners with the public and private sectors to implement these systems. In Marietta, for example, smart traffic technology turns traffic lights green for firetrucks. This has decreased firetruck crashes to zero in the six years since installing it, Mulligan said.

Applied Information also has helped outfit buses in some school systems that communicate with smart cars, to tell the cars when they are planning to stop. The beacons help warn drivers to slow down or prompt autonomous cars to do that on their own.

Intelligent left turns work in the same manner, said Brandon Branham, Peachtree Corners assistant city manager. The Gwinnett County suburb has been one of the more forward-leaning, tech-friendly cities in Metro Atlanta, given its Curiosity Lab off of Peachtree Industrial Boulevard.

The city installed this system on the Peachtree Industrial/southbound left turn into the NAPA Auto Parts store on Business Park Drive. This is fittingly just north of the Curiosity Lab’s home on Technology Parkway, which has its own smart signal at a blind, three-way stop at Engineering Drive.

“It’ll tell you that it is unsafe, based on the algorithm, to turn left. You can still turn left, if you want to. But we are just giving you some notification that it may not be the safest time to turn left,” Branham said in promotional material about the technology.

Does that not speak to human nature? Sometimes a driver is on the fence about whether to risk that left turn. Maybe their decision is simply influenced by how long they have waited and not how safe turning is. They need a better prompt from something objective.

The Peachtree Industrial signal, Branham said, “Saw upwards of six car crashes annually. Since piloting this technology, police reports have shown a 25% decrease.”

Preventing a crash or two per year does not sound like much, but that certainly matters to the people in those crashes and the countless others inconvenienced by them.

And that is in just one intersection. Imagine if one crash per year was prevented at a city’s ten worst intersections. Extrapolate that over ten cities. And these are just small changes.

The toll of an ill-fated left turn is often far greater than crash damage and traffic delays. Lives are changed and lost, which makes this innovation personal for Mulligan. “A friend of mine, young Liam Haywood, was killed in such a situation,” Mulligan recounted in a video by Wavetronix, the intelligent signal’s manufacturer. “He was on a motorbike and a motor car just turned left in front of him and killed him and snuffed out a young, talented life at 20 years old.” Mulligan then fought tears, saying, “And that provided us the motivation to do something about it.” He calls the technology “Liam’s Light” and hopes there will be many more adaptors like Peachtree Corners.

Mulligan acknowledges that some cities embrace these innovations easier than others, and he credits several Atlanta suburbs — Alpharetta, Marietta, and Peachtree Corners, among others — for taking the risk and spending the money to see if this paradigm shift works.

“You need early-adopter cities; you need forward-leaning cities,” Mulligan said. These cities are more willing to take risks on these technologies — some would call these experiments — in the name of safety and traffic efficiency. When more rigid municipalities see the case studies work, they have hard data to show the innovations are worth implementing.

“You’d be amazed how much resistance you get from the guys that have been doing the same things for 40 years,” Mulligan said.

Mulligan and his associates continue finding the next safety frontiers, despite any headwinds: “We just keep pushing forward. We only know one way and that is to put our head down and push forward.”


Doug Turnbull, the PM drive Skycopter anchor for Triple Team Traffic on 95.5 WSB, is the Gridlock Guy. Download the Triple Team Traffic Alerts App to hear reports from the WSB Traffic Team automatically when you drive near trouble spots. Contact him at Doug.Turnbull@cmg.com.

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