According to the summary, Trey Church was driving a Subaru behind two cars towards Hirangi Rd from the Turangi town centre.
On the approach to a right hand corner he pulled into the oncoming lane and overtook both vehicles, but lost control when he braked as he came back to the correct side of the road, sending the car into a swerve.
The car did a 90 degree turn and skidded across the road mounting the kerb and crashing into a tree.
All three teenagers were trapped in the car.
During the court appearance, Trey Church's grandmother, who was in the public gallery, made an appeal for restorative justice.
Judge Chris McGuire said although Kane Church had indicated he would be interested in taking part in restorative justice, representatives of Mr Bell did not wish to engage. Judge McGuire convicted Trey Church on both charges and remanded him on bail for a probation report.
He was also ordered not to drive a motor vehicle. He will reappear in court for sentencing on July 19.