South Carolina ? The driver of a tractor-trailer was charged Monday with drunken driving after slamming into a hayride and killing four people, including a toddler.

The crash happened Sunday night, when the 18-wheeler hit a flatbed trailer and the tractor pulling it. Sixteen people were injured; two were hospitalized.

Investigators said it was unclear how fast the truck was going, and they would not disclose the truck driver’s blood-alcohol level.

Jake Davis Jr., 51, tried to swerve to the left to avoid overtaking and hitting the hayride, authorities said. At the same time, tractor driver Franklin Jones Jr., 33, swerved in the same direction to avoid being hit, said Highway Patrol Lance Cpl. Paul Brouthers. The flatbed trailer did not have tail lights, Brouthers said.

Authorities identified the dead as Jerry Wayne Jones, 31; Shiwanna Lowery, 15; Freddie Lynn Jones, 24; and his 2-year-old son, Javon Jones.