It tied up traffic for hours, but a rockslide Tuesday afternoon on State Route 840 in Williamson County may only be the start of problems for the Tennessee Department of Transportation.
Engineers blame the weather for causing the rockslide that caused a tractor-trailer to veer into oncoming traffic before coming to a stop.
While TDOT acknowledges the same thing could happen again, it said there are plans in place to keep drivers safe.
"To some degree, it's unpredictable," said TDOT spokeswoman Deanna Lambert.
"We're so thankful that no one was hurt."
A large wall of rock along State Route 840 gave way, closing the road for hours.
"I'm lucky to be alive, really. You know, you can look at the truck, it's totaled out. And the whole front end, I had no control," said truck driver Danny Rogers.
TDOT engineers suspect a second spot about 75 feet from Tuesday's slide could be next and must be removed.
As it stands, TDOT has a four-step plan to manage rockslides. The first tactic involves fencing along areas more prone to slides. Such fencing is located along parts of Interstate 440 in Nashville.
"Those fences are put strategically in those areas, because those areas and those rocks are subject and more prone to falling," Lambert said.
The plan also includes wider shoulders on new construction, rock anchors and a special hazard database that helps TDOT keep tabs on possible problems.
A combination of extreme cold then record heat likely added up to spark a problem.
"In the winter time, these rocks lay out there in the extreme cold, and then it rains and there's water that comes in them and it kind of cracks them open. And then, in the summertime, in the extreme heat, they lay out there and bake. So, over and over and over, this process kind of breaks down the structure of the rock," Lambert said.
So, theoretically, it could happen again.
It's the nature of the beast for a business that can, at times, be entirely unpredictable.
"It's something that TDOT is aware of, but as far as monitoring on a daily basis, we'd be spending all day every day looking for rocks to fall," Lambert said.
As bad as the risk might be in Middle Tennessee, the biggest risk could be in East Tennessee, where TDOT uses more fences to cut down on the rockslide risk.
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