Appearing before Judge Peter Hobbs in Masterton District Court this week, the 31-year-old sales representative pleaded guilty to a charge of careless driving.
The accident happened two days before Christmas, December 23, last year on State Highway 2, just south of Masterton at the Norman Ave turn off at Waingawa.
Police prosecutor Sergeant Jodie Lawrence said Johnson crashed into the Subaru as the driver waited to turn right into Norman Ave, hurling the Subaru into oncoming traffic.
The driver of the oncoming vehicle had to be "extracted" from the car and spent four days in hospital after surgery on his legs, Ms Lawrence said.
When interviewed by police, Johnson stated he didn't remember seeing the car, she said.
Defence lawyer Louise Elder submitted the Subaru's driver should have pulled to the left of the road and waited for other highway traffic to pass before turning right.
"They did not."
Her client was concerned about the "tail-gating" of a following car which distracted him, Ms Elder said.
"The car was impatient behind him."
"It's a situation where possible special reasons might exist."
Judge Hobbs convicted Johnson, remanding him at large for an emotional harm report to be completed and sentencing on July 22.
