Johnson pleaded guilty to careless driving causing injury at an earlier appearance, stating he was distracted by an impatient driver following him and trying to overtake him.
His lawyer, Louise Elder, said the driver of the car waiting should not have been in the middle of the road to turn right.
While her client was "extremely remorseful" for the crash and injuries the victims suffered, a "matrix of circumstances" had led to the crash from the car following distracting him to the car in front stopped and waiting to turn right, she said.
"There were a mixture of things. The car being in the middle of the busiest road in the Wairarapa to the driver behind ... if the driver had pulled to the left like many drivers do, this accident would not have happened."
However, prosecutor Sergeant Garry Wilson said the driver of the car slammed into was legally in the right, indicating he was turning.
Johnson should have been more aware of his surroundings, he said. "He was more concerned with what was happening behind him than what was going on in front of him ... the victim was abiding by the road rules," he said.
Judge Arthur Tompkins declined the special circumstances application.
He said Johnson tried to avoid the car by swerving left, but was unable to avoid crashing, hitting the rear left of the car waiting to turn, flinging it into oncoming traffic.
Johnson was ordered to pay $750 emotional harm reparation and disqualified from driving for six months.