Jayden Nathan Wayne Sheehy (27) thought the target of his wrath had been selling his ex-partner drugs, but he admitted to police it was a case of "mistaken identity".
The incident, which took place on July 25 last year, began in North Dunedin. The defendant tailgated the victim to Maori Hill.
Near John McGlashan College Sheehy shunted into the rear of the BMW and continued the pursuit as the panicked man tried to escape.
When the victim tried to pull a U-turn and got stuck, the defendant reversed into him at speed, prompting the man to flee on foot.
The episode resulted in the defendant being charged with dangerous driving and assault with a weapon, the Dunedin District Court heard yesterday.
He was bailed to a Waimate address and barred from driving or returning to Dunedin.
But Sheehy’s compliance barely lasted a week.
At 3am on August 2, he drove to his ex-girlfriend’s home in Dunedin where she was home alone.
Wielding a Taser, he confronted the woman, activated the weapon and began "waving it around", the court heard.
The victim shut herself in a bedroom and contacted friends.
They arrived and were similarly threatened with the stun-gun before Sheehy left the scene.
But an hour later he was back.
The defendant smashed 12 windows around the property and damaged two televisions inside the home.
Judge Emma Smith said the fact Sheehy had chosen to drive to the house in the early hours was significant.
It had clearly been done to cause maximum distress to the victim, she said.
"You’re unable to restrain your violent tendencies," Judge Smith said. "You’re a risk to the public, you’re a risk to your partner."
She described Sheehy’s excuse for the road-rage incident as "extraordinary", saying he seemed to lack remorse.
The defendant refused to attend restorative justice.
Defence counsel Brendan Stephenson said his client was struggling with the breakdown of his relationship but had since "changed direction" in his life.
He argued Sheehy should avoid imprisonment, and Judge Smith agreed — "by the finest margin".
The defendant was sentenced to 12 months’ home detention (the maximum such term) and was disqualified from driving for a year and a day.
He was ordered to pay reparation of more than $10,000 for damage to the car and windows.
