Sophie Boyeldieu, 21, was handed down a 12-month suspended prison sentence at York Crown Court, after the jury heard her vehicle had drifted back and forth across the Selby bypass in Yorkshire at speeds of up to 60 mph, with her baby son, Aidan in the back seat.
After almost crossing the road on to the opposite verge, she eventually crashed into a minibus travelling in the opposite direction and her Honda Jazz ended up on its roof.
Olivia Checa-Dover for the prosecution said Aiden's leg was out of his seat restraint and his upper body was free to move about. She told the court: "Had Aidan been properly strapped in, it might have prevented his death."
Boyeldieu's barrister, Robert Underwood, said his client will be "forever be haunted" by the events, and that she was "traumatised by the suggestion her failure to strap baby Aidan into the child seat correctly could have played some part in the tragedy."
Recorder Eric Elliott QC gave Boyeldieu a 12-month prison sentence suspended for two years, along with an order to complete 150 hours of unpaid work. He also banned her from driving for two years and ordered her to re-take her driving test.
It was revealed that Boyeldieu had been caught speeding six months previously, but had declined to go on a driving awareness course.
Eric Elliott QC told her: "It is a very great shame perhaps you didn't take part in the driving awareness course. If you had, we might not be here today and your son might still be alive."
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