The scientists found something significant.
"As a result of the survey for this entire corridor, we identified, I believe, it's over 155 sites," said Matt Wilkerson who heads up the NCDOT's archeology unit.
Anytime NCDOT plans to build a road, federal law requires that it documents historic or even prehistoric sites in the construction corridor.
"NCDOT takes its stewardship responsibility very seriously," Wilkerson told ABC11.
He said that is why NCDOT formed the archeology unit more than 30 years ago, deciding it would be the most efficient way to handle that responsibility.
In the case of the Triangle Expressway, which will complete the 540 outer loop around Raleigh, most of the sites that archeologists found were not in the direct path of the asphalt.
There was one exception -- an area in southeastern Wake County below Garner near Williams Crossroads.
So, the team got to work.
For three months, they dug up a large area in 540's path and sifted every inch through large screens.
There was so much work that they contracted with other archeologists such as Susan Bamann with Commonwealth Heritage Group.
She showed us pieces of a pot that was apparently dropped and broken.
"It probably dates to somewhere around 500 A.D., something like that," she said. "We'll probably be able to reconstruct much of the pot."
The inside of that pot could provide a trove of information.
WATCH: Archeologist explains more about the artifacts found
"We'll probably do some chemical analysis on it. It's possible to extract residues from the wall of the ceramic vessel and determine the kinds of foods that were being cooked in the vessel," Bamann said. "That's really exciting,"
Those artifacts and many others, including tools, all date from about 1,500 years ago and were found about 12 inches below the surface.
The archeologists surmise this was a popular campsite for the nomadic natives who were North Carolina's first inhabitants.
But the campsite's origins apparently came thousands of years earlier because as they went deeper, the archeologists found more artifacts including what they call "points."
Bamann showed us a collection of those "points" -- stone tools with sharp edges.
"These are from the archaic period," she said. "This one's from the early archaic period, so 6,000 to 8,000 B.C."
The excavation has just ended but when we visited, the scientists were sifting the last of the dirt removed from the site.
As they worked, heavy equipment rumbled nearby and blasting occasionally sent shock waves through the air and ground.
But the archeologists never flinched.
One of the most exciting finds unearthed on the dig was a broken and once polished piece of stone with holes drilled in it from about 10,000 years ago.
"Probably a piece of personal adornment, jewelry, if you will," Bamann said, and she added, "it's a two-holed item that someone would have suspended as a piece of personal decoration or ornamentation. At least that's what we believe these items are. So, finding something that's a personal item from someone who lived here, and camped here is, I think, is just one of those things that makes all of this extra interesting because it's a little bit of a glimpse into the past."
Bamann said this was obviously a popular camp for hunter-gatherers.
Some of the items found here revealed just how far those people may have roamed.
Bamann pointed at the projectiles, noting that some were made from materials that wouldn't have been found in the area near the campsite.
"These are all fashioned from stone, some of these from the stone source that we associated with the Uwharrie Mountains," she said.
Those mountains are in Montgomery County nearly 100 miles west of Wake County.
The artifacts collected at the site will eventually end up at the North Carolina Office of State Archeology.