HAYES — The South Dakota Highway Patrol is investigating a crash that injured three people Thursday afternoon one mile east of Hayes in Stanley County. Patrol spokesman Tony Mangan says a Chevy Traverse with four occupants crossed the center line and struck the rear tire of a trailer being pulled by a Kenworth semi-truck, causing the Traverse to roll over. The 26 year-old female driver of the Traverse and four year-old male passenger suffered life-threatening injuries. Restraint use by the four year-old male is under investigation. The driver was not wearing a seat belt. A 26 year-old female passenger wasn’t not injured while a 61 year-old female passenger suffered serious, non-life threatening injuries. The 26 year-old was using a seat belt while the 61 year-old was not. Two of the four Traverse occupants required assistance exiting the vehicle. The three injured occupants were transported by ambulance to Avera St. Mary’s hospital. The 26 year-old driver and four year-old male passenger were then airlifted to a Sioux Falls hospital. The 42 year-old male driver of the semi was using a seat belt and not injured in the crash. The names of those involved have not been released.