Happened when I lived in northern Maine, and I passed the accident scene minutes after. Her S-10 Blazer was destroyed, she died instantly. The truck driver who hit her head on said he saw her fussing with the baby in the back seat. She crossed the center line and was decapitated. The infant was without a scratch.
There was a similar accident near Syracuse, NY on interstate 81. They’re not sure what happened other than the car crossed the grassy median, flew up into the air and landed immediately in front of a tractor trailer. The car was obliterated and the mother and two girls (her own daughter and her best friend’s daughter) were killed instantly. The scene of the accident was closed for HOURS while they were picking up the pieces.
Suspicion was that she had got distracted somehow. There was also question as to whether the little girls were buckled in. I really don’t recall the final conclusion on it.