COLLIN COUNTY, Tex. -- An overturned semi on southbound U.S. Highway 75 triggered a number of incidents that ultimately shutting down southbound lanes on Wednesday afternoon.

Officials with the Texas Department of Transportation say in an attempt to re-route traffic to a separate frontage road, a different semi hit another vehicle.

That's when northbound U.S. 75 was shut down to land a medical helicopter.

While northbound lanes were shut down, a 5-car pile-up resulted in the northbound lane, calling for yet another medical helicopter to the scene to attend to accident victims.

Both the north and southbound lanes of U.S. Highway 75 are said to be open again, however traffic is reportedly running slowly as authorities are still on the scene investigating the cause of the initial overturned semi.