A major accident in the right-hand lane of Highway 281 South left a young boy dead, and a man in critical condition Monday morning. 

The crash happened around 10:15 a.m., just south of Thousand Oaks near the Donella exit, police said.

Police said a tractor trailer had mechanical problems and stalled out alongside the road. Part of the truck was still jutting into the right-hand lane.

A white SUV, driven by a man in his 40s, slammed into the back of the parked 18-wheeler, police said.

Two children were in the backseat. A little boy, said to be between 7 and 10 years old, was pronounced dead at the scene, while a little girl escaped the crash uninjured.

The driver, whose identity has yet to be released, was airlifted from the scene, and is listed in critical condition.

"You can see the roads out there are pretty slick," said San Antonio police Sgt. Javier Salaza. "We don't know, at this point, if the weather was a contributing factor in the crash, but we are certainly looking into that."

Traffic investigators were expected to finish their report by the end of the day Monday.

"At this point, we can't rule out any charges on anybody, but they are certainly a possibility," Salaza said.