Maryland State Police closed Interstate 83 in both directions for an hour Sunday after an accident near Hereford in northern Baltimore County sent one person to Maryland Shock Trauma Center in Baltimore and two others to area hospitals.

State police said the accident occurred about noon, when a car backing up on the northbound shoulder of the expressway's median swerved into the travel lane and the path of a pickup truck towing a boat. The passenger of the car was flown to Shock Trauma center while the driver of the vehicle was taken to York Hospital and the driver of the pickup truck to Greater Baltimore Medical Center. Their conditions were not known.

State police said the accident scene was cleared, and the highway reopened by 1 p.m.