Laura Ward had cannabis, diazepam and amphetamines in her system when she hit Aiden Platt, 20, in Barnstaple, Devon.
Ward, 30, of Fleet, Hampshire, admitted causing death by careless driving while under the influence of drugs.
The judge at Exeter Crown Court handed her a 20 month jail sentence but it was suspended for 18 months because she has a five-month-old son.
More on the sentencing and other stories from Devon and Cornwall
Footage was shown to the court of Ward's car pulling out at Sticklepath Hill without any warning with Mr Platt being thrown into a traffic light post on 2 August 2015.
At the police station she was "mumbling and incoherent and slumped onto the counter with her head in her arms", the court heard.
Three months after the crash, Ward became pregnant with her son.
Judge Geoffrey Mercer told her that Mr Platt 's death has had a "devastating effect" on his family and friends.
"Quite simply, you should not have been driving," he said, but he added courts were "reluctant to send the mother of a young child to prison".
He said: "Your son is five months old and I am just persuaded for that reason and that reason alone I can properly suspend this sentence."
Mr Platt's family said they did not want to comment after the sentence.
Ward was also given a curfew for four months and banned from driving for four years.
A drug driver who killed a young motorcyclist has been spared a prison sentence because she has a young child.