Crews are looking into what caused a noticeable dip in the last few weeks. Engineers say there could be an old mine shaft beneath the parkway.
The KYTC says the emergence of sinkholes around the nation like the one at the National Corevette Museum in Bowling Green has raised awareness.
"We get a lot of reports from the public, occasionally phone calls," said Keith Todd. "We get information out through our website and also through our Facebook page. Ironically, one of the best sources on road hazards we have happens to be bus drivers."
Drilling work is supposed to last three to four days, but the road could be closed longer.
You can go to www.511.ky.gov to report road hazards and download a smartphone app.