We saw a doozy on I-20 Wednesday afternoon. A tanker truck and a tractor trailer collided just after 4 p.m. on I-20/westbound just before Six Flags Dr. (exit 47) and eventually completely shut down the interstate in that direction. Traffic was a nightmare and my colleagues and I with WSB Triple Team Traffic went into hustle mode. Our Traffic Troopers, commuters who call us with info, gave us the alert before the police or GDOT did. » RELATED: I-20 reopens in Cobb County after massive fuel spill cleanup “I got the original call from traffic trooper Joey. At the time, he told me that there was a crash involving two tractor trailers and some cars,” reporter Jill Nelson said. She and teammate Alex Williams began sending both myself and Newschopper 2’s Jason Durden vital information on the crash. “The left lane was still moving at that point. By the time Alex found it on the WSB Jam Cam, they had closed all lanes.” Whereas the WSB Skycopter flies on a fixed rush hour schedule, Durden and Channel 2 Action News’ helicopter fly a la carte when various news stories break. He got to the scene within minutes and began relaying information back to us and to Channel 2 viewers both on TV and social media. The Traffic Team and I broke into programming on News 95.5/AM750 WSB with the traffic RED ALERT and also sent push notifications out on the Triple Team Traffic Alerts App and the WSB Radio App. This is Atlanta traffic’s version of a tornado warning; every second matters when someone is planning their commute. As we began to learn that this was a tanker truck overturned and that it had nearly 9,000 gallons of fuel, we knew this wouldn’t be an ephemeral closure. “When crews started spraying foam on the fuel spill, we knew it was going to be a bigger deal — then the DOT notes updated saying it was a Hazmat situation,” Williams explained. Williams discovered that at least 100 gallons of fuel had actually spilled. With this crash happening not far from the Chattahoochee River bridge, cleanup crews had to treat the cleanup with extra care. One insight that traffic reporters give that an app like Waze, Google Maps or Apple Maps cannot is just how severe or specific a problem is. When Durden, Williams, Nelson, and I processed what we were seeing, we knew this would not be the average interstate closure and we reported as much. Mike Shields joined WSB Triple Team Traffic in June and had just been on I-20, before arriving at the WSB studios in Midtown Atlanta before 5 p.m. He found out about the closure just as he pulled into the parking deck. » RELATED: Georgia roads reopen after tanker truck crash, oxygen leak “This was the largest traffic event I have covered and the domino effect on all the other interstates was unreal,” Shields said. The backup in the already stacked I-285 and I-20 interchange in Fulton County was extreme. From the WSB Skycopter, I saw I-285/southbound start jamming hard at Paces Ferry Road (exit 18) and stay slow all the way to I-20. The right lane line to exit at Hollowell Parkway (exit 12) started before the Chattahoochee River bridge, as people sought an alternate. Indeed, the impacts on side roads like Hollowell/Highway 78, Camp Creek Parkway and Highway 166 were extreme. Fulton Industrial Boulevard was jammed, as police diverted I-20/westbound traffic onto that exit before the closure. “Phone calls I received were people asking about is there any way to get around it,” Shields said. And while there technically were open roads, those alternates were gridlocked. Calls to WSB about alternate routes got trumped, however, by calls of frustration. “Most calls we got were that people were blocking emergency vehicles from passing on the shoulder and they hadn’t moved in hours,” Nelson said. And we saw this in the Skycopter: drivers stuck in the closure between Fulton Industrial (exit 49) and the crash scene began driving the wrong way on the shoulders without any directive from the police. This is completely illegal and dangerous. It prevented more rescue units from getting to the scene. Additional equipment instead had to go up to Six Flags and turn around the wrong way. We watched above as police eventually got a couple hundred vehicles turned around and exiting one at a time, the wrong way up the Fulton Industrial entrance ramp and off of the freeway. Nelson did not mince words: “I’ve covered plenty of bad crashes before, but this one stands out because of the jam that drivers caused themselves, by blocking up the shoulders. It took over two hours to finally get everyone out of there who was stuck.” » RELATED: Report finds Atlanta has some of world's worst traffic The crash cleanup eventually lasted into the night, with overnight traffic guru Steve Winslow taking the Traffic Center helm at 8:30 p.m. The crash lasted his entire shift. “The biggest issue for re-opening I-20 seemed to be the safety workers’ need to unload the overturned tanker’s load of fuel. Having to drill into a hole into the overturned tanker to siphon the combustible fuel out safely took at four hours alone,” Winslow explained. He said that this tedious process forced the closure of I-20/eastbound, the opposite direction, starting at Thornton Road (exit 44). The scene didn’t clear until almost 4:30 a.m., over 12 hours after the wreck happened. Our entire team was in unison about where this wreck ranks. “This one,” Winslow said, “made a “normal” overnight become almost as intense as a Friday evening commute.” “Aside from the [I-85] bridge collapse, this is probably the second-worst single traffic incident I’ve ever seen, due to how long it lasted and how much it impacted surface streets — even as far back as inside the Perimeter,” Williams, who joined Triple Team Traffic in 2015, recalled. And I agree with my crew. This I-20 tanker truck crash ranks as one of the worst single wrecks, in terms of traffic impact and the length of closure, that I have seen. It once again shows how vital our roads are and how just one problem can delay people for miles around for hours. The I-20 extended closure also shows how important planning your commute and keeping your radio and phone on for updates during that drive is, too. » RELATED: Metro Atlanta's 10 most consistently awful traffic hotspots Doug Turnbull, the PM drive Skycopter anchor for Triple Team Traffic on News 95-5 FM and AM-750 WSB, is the Gridlock Guy. He also writes a traffic blog and hosts a podcast with Smilin’ Mark McKay on wsbradio.com. Contact him at Doug.Turnbull@coxinc.com.