It happened around 5:30 a.m. Images from Department of Transportation cameras showed the patrol car may have gone down an embankment.
According to Raleigh police, an officer was driving on the ramp from Edwards Mill Road to westbound Wade Avenue when the cruiser hit a patch of mud on the roadway.
The officer lost control and slid to the edge of a wooded area. He was not injured.
The accident temporarily closed the right lane to traffic as authorities cleared the scene.