A driver veered into oncoming traffic early Sunday morning and slammed into a semitruck, killing a child and sending two adults to the hospital, according to the Idaho State Police.

The kid, who was in a child safety seat, died of injuries at the scene. The driver, a 39-year-old woman from Roseville, California, and a passenger, a 35-year-old woman from Butte, Montana, were transported by air ambulance to the hospital, police said. Both women were wearing their seatbelts.

The semitruck driver, a 47-year-old man from Twin Falls, Idaho, was also wearing a seatbelt and wasn’t transported to a hospital, police said.

The collision in southern Idaho closed the highway for six hours, and remains under investigation.