A Montgomery County police cruiser hit a pedestrian and seriously injured him while driving on patrol Thursday night in the Wheaton area, police said.

The accident happened as the officer drove south on Georgia Avenue and struck the man, who was in the road near the intersection of Blueridge Avenue about 9:27 p.m., said police spokesman Tom Jordan.

The pedestrian, a 21-year-old man from Wheaton, was taken to a hospital with life-threatening injuries. On Friday, police said he was expected to survive.

Police said the man was not in a crosswalk when the collision happened.

Officials shut down northbound and southbound lanes of Georgia Avenue near Arcola Avenue to investigate, police said. The accident remains under investigation.