A truck driver was on a cocktail of drugs and alcohol days before a fatal crash
Mohinder Singh pleaded guilty to culpable driving at a Melbourne court
The 48-year-old was behind the wheel when he hit and killed four police officers
The officers were struck by Singh s semi-trailer while impounding a Porsche
A court heard the driver was drug-f ed and hadn t slept for days before crash
Singh was sentenced on Wednesday to 22 years in prison for the atrocity