A mother took cocaine before crashing into a double-decker bus, killing her and her one-year-old son who was sat in the passenger seat.
Sian Goffin, 31, who had taken cocaine, suffered fatal injuries in the collision in Mullion, Cornwall, in October last year.
Her son, Jago Bawden, was also fatally injured and died three days later in Bristol Children's Hospital, Cornwall Coroner's Court heard.
The crash also injured 27 children who were travelling to school.
Post-mortem examinations found Ms Goffin and her son, who were from Mullion, had both died from traumatic brain injuries.
