A 3-year-old child was killed early Wednesday in a two-vehicle wreck near Six Flags that also injured the child’s mother and younger sibling, Cobb County police said.

The wreck, which happened about 2:30 a.m., was the first of two fatal overnight crashes on metro Atlanta interstates.

Cobb County police spokeswoman Alicia Chilton said a 2002 BMW 530i was westbound on I-20 near Six Flags Parkway when it was rear-ended by a 2008 GMC Yukon sport utility vehicle.

The BMW driver, 23-year-old Mikkiala Green of Douglasville, was taken to Grady Memorial Hospital in critical condition, Chilton said.

Green’s 3-year-old son died at the scene from injuries he sustained in the collision, according to Chilton. Her 1-year-old son was injured and taken to Children’s Healthcare of Atlanta at Scottish Rite.

Police have not released the names of the children or the younger boy’s condition.

The Yukon driver, 37-year-old Tyrone Gantt of Austell, was treated on the scene for minor injuries, Chilton said.

She said the collision remains under investigation, and asked that anyone with information call investigators at 770-499-3987.

About an hour after the I-20 wreck, a tractor-trailer was involved in a fatal crash on I-85 in Coweta County.

According to the Georgia State Patrol, the truck was traveling on the right shoulder of the northbound interstate at Mile Marker 53 when the truck hit a guardrail and a concrete traffic barrier and became engulfed in fire.

The driver, identified as James Wesley Prater, 46, of Camilla, was unable to exit the vehicle and died in the crash, GSP spokeswoman Tracey Watson said.