EMERSON -- A mother is killed and her two young children are injured after a tractor-trailer rolled over on the family's SUV with the kids inside.

The father is also hurt from the accident on Highway 41 in the town of Emerson in Bartow County.

The driver of the big rig has been charged with DUI.  Police say he was outside the tractor-trailer when it started to roll.

“The driver of the truck failed to set the parking brake,” Emerson Police Chief Stan Bradley told WSB'S Richard Sangster.  The truck may have been going more than 30 mph when it slammed into the SUV.

Emergency crews worked for two hours to reach the family that was trapped inside the truck. They kids, ages 2 and 4 were strapped in car seats. They were taken to Children’s Healthcare of Atlanta in serious but stable condition.

The young family from Cartersville was returning from a family dinner in Dallas.

The crash happened around 9 p.m. Thursday.