A man in a wheelchair was struck by a hit-and-run driver in Charles County on Saturday night in one of what authorities described as at least two serious traffic incidents in the Washington area over the weekend.

The man in the wheelchair was trying to cross St. Charles Parkway in the Waldorf area just after 11 p.m. when he was struck by a vehicle that left the scene, the county sheriff’s office said.

Police and rescue personnel arrived on the scene at St. Thomas Drive and thought the man’s injuries were possibly life-threatening, the sheriff’s office said.

The man, a 34-year-old resident of Waldorf, was flown by helicopter to the Prince George’s Hospital Center. He was said to be in stable condition there, the sheriff’s office said Sunday afternoon.

The man’s name was not given, and it was not clear where he was going.

According to the sheriff’s office, evidence gathered at the scene suggested the vehicle that hit the man may have been a truck.

In the other incident, a man, woman and child were injured Sunday evening in a collision involving a car and a tractor trailer on the Capital Beltway in Prince George’s County. First reports indicated that the child’s injuries were extremely serious, said Mark Brady, spokesman for the county fire department.

All three of the injured had been in the car, Brady said. The man and woman were extricated from the vehicle after being trapped for a time. The adults’ injuries appeared to be serious but not life-threatening, he said.

Brady said the crash occurred about 10 p.m. on the inner loop between Central Avenue and Ritchie Marlboro Road.

The crash shut down all lanes of the inner loop at the site, Maryland State Police said. The site was in the Largo area, about three miles northeast of Joint Base Andrews.