The woman, who filmed the incident on her mobile phone, suffered scratches and bleeding to her face and neck.
Hautapu pleaded guilty to criminal damage and assault occasioning bodily harm in the Fremantle Magistrates Court last month.
The court was told he was serving a suspended jail term for unrelated matters at the time of the road rage attack.
At today’s sentencing hearing, his lawyer Justin Geoghegan told the court Hautapu had been at Adventure World with his partner and one-month-old baby on the day of the incident.
His partner was driving home when she was forced to swerve to avoid the victim’s vehicle as they attempted to merge on the freeway.
Attack ‘a complete overreaction’
Mr Geoghegan said his client’s response was a complete overreaction and Hautapu recognised his actions were unjustifiable and grossly inappropriate.
“He’s trying to ensure that that loss of control never happens again,” Mr Geoghegan said.
“He owes that to his family and he owes that to the victim.”
He asked for a suspended sentence, but magistrate Elizabeth Langdon said the incident was serious and there was a need to show that such conduct was not tolerated in the community.
“You clearly are a man of a short fuse who decided very quickly to take the law into your own hands,” Ms Langdon said.
“Most people in the community don’t tolerate this kind of behaviour. Really, they are repulsed by it.
Hautapu was sentenced to 10 months in prison and ordered to pay $700 to repair his victim’s vehicle.
He will be eligible for parole after five months.