The teen was tailgating and repeatedly crossing the centre line in an attempt to pass before he crashed into oncoming traffic.
The teen was convicted on all four charges he faced yesterday.
He will be sentenced in the Dunedin District Court on two counts of dangerous driving causing death and two counts of dangerous driving causing injuries, in order to face more appropriate penalties than those available in the Youth Court.
The teenager, whose name remains suppressed, was remanded into Oranga Tamariki custody.
Judge Michael Turner said the sentencing options in the youth system were not appropriate for the teen, who was described by police as having a "cavalier" attitude and showing no remorse after the crash.
He had been discharged from previous Youth Court proceedings just three days before the crash and had previously been warned that his manner of driving could lead to a fatal crash, the court heard.
The teen also started by claiming "wrongly" he had fallen asleep, the judge said.
Reading from the summary of facts, Judge Turner revealed the details of the crash for the first time.
The teen was driving back from Invercargill to Dunedin when he started tailgating another car.
In a passing lane, the two cars began overtaking cars in tandem.
At the end of the passing lane the teen remained behind the first car and crossed the centre line four times in an attempt to pass.
It was always busy.
On his fifth attempt, 1km south of Waihola, with
his vehicle halfway into the other lane, an oncoming car swerved to avoid a head-on collision.
The following car was unable to get out of the way.
The resulting crash killed two mothers and injured two others in a family group heading from Dunedin to Queenstown in a convoy.
The victim impact statements made sad reading, Judge Turner said.
The teen's offending was too serious, the risk he posed to the community too high and the consequences in the Youth Court were inadequate for the matter, the judge said.
The teen will be sentenced on August 18.
-- Court Reporter
