A Washington, D.C., man was killed and his wife was critically injured Wednesday night when a tractor-trailer struck them after a collision on Interstate 95 in Harford County, according to Maryland State Police.

Leonard Clark, 38, and Kimberly Clark, 39, had been driving a Dodge Charger and a Dodge Durango when they were involved in an accident on northbound I-95 north of Mountain Road, said state police Cpl. Kevin Watkins of the JFK Highway barracks.

The two exited their vehicles and were standing in the roadway when they were struck by a tractor-trailer at about 11:20 p.m., Watkins said.

The husband was pronounced dead at the scene, according to Watkins. The wife was taken to Maryland Shock Trauma Center, where she remained in critical condition, he said.

The roadway was closed until 5:26 a.m. due to the investigation, according to Watkins.