When the last leg of Charlotte’s outer loop opened in northern Mecklenburg County in 2015, it marked the end of an exhaustive 27-year construction project.
As traffic poured onto Interstate 485, crashes mounted — enough to make the N.C. Department of Transportation consider, then reject, lowering the beltway’s 70 mph speed limit.
NCDOT says it inadvertently published notice on its website this week that the speed limit on a portion of I-485 would be lowered to 65 mph. Department officials told the Observer they’ll keep studying the issue but lowering the speed limit is off the table, for now.
The loop averages 154,000 vehicles a day on its busiest stretch, at N.C. 51 in southern Mecklenburg County, according to 2018 state data. That area is also where the most crashes occur.
But in the three years after the final leg opened, total crashes on the full loop rose sharply compared to the previous three-year period, DOT data shows. Crashes more than doubled in segments totaling 40 miles of the loop’s 67 miles.
Some of the largest increases are on segments closest to that last leg, which is between N.C. 115 and I-85 north of Charlotte. Traffic volume surged when the final link opened.
Crashes in the segment between N.C. 115 and N.C. 27, on the northwestern part of the loop, rocketed 265% higher. Rear-end and sideswipe collisions — common accidents in congested traffic — rose seven-fold and four-fold in that segment, respectively. Crashes between I-85 and Albemarle Road, on the northeastern part of the loop, rose 123%.
State Traffic Engineer Kevin Lacy attributes much of the increase in crashes to the higher volumes of traffic the beltway carries since it was completed. Traffic peaks when the economy is humming, as it is now, he added.
The rate of crashes — the number that occurs for every 100 million miles that vehicles travel on the loop — has also risen, he said. But some segments had crash rates that were higher than the state average even before the beltway was completed.
Lower speed limit on I-485?
In response to the growing number of crashes, Lacy said, DOT considered lowering the 70 mph speed limit to 65 mph. The department inadvertently released a press release this week announcing the speed limit change for a portion of the loop, then withdrew it.
“Right now, I believe consistency is most important,” Lacy said. “We’ll continue to monitor it, but if current trends continue within statistical norms of what to expect, we won’t likely be making any changes.”
The first segments of I-485 to be built, in southern Mecklenburg, give drivers particular problems. While newer segments have six to eight total lanes of traffic, the loop at Pineville, Ballantyne and Matthews has as few as two lanes in each direction.
“Anytime you have a lane change, say from three lanes to two, especially during the peak hours, that’s generally when you’re going to see congestion,” Lacy said.
Those southern Mecklenburg segments have had, by far, the highest total number of wrecks on the loop. The 20-mile stretch from Matthews to west of I-77 racked up nearly 3,000 accidents from 2015 to 2018, an average of nearly three a day.
Help is on the way, but it might temporarily increase the number of crashes.
Construction began last month on a $290 million project that will add one toll lane in each direction of I-485 between I-77 and Independence Boulevard. One non-toll lane will be added both ways in the stretch between Rea and Providence roads. Work is expected to be completed by late 2022.
Speed limits will be lowered in the work zone of the I-485 toll lane construction, Lacy said, but DOT’s experience is that crashes will go up there while work is underway.
The department says drivers should slow down, maintain a safe following distance and keep their eyes on the road in the work zone. Cars that are in accidents, but not disabled, should be moved to the shoulder of the road.