Two teenagers have been locked up for five years after admitting causing the death of a 17-year-old girl as they raced their cars.
Olivia Alkir, from Efenechtyd, Denbighshire, died after a two-car crash on the B5105 on 27 June.
She was a passenger in a Ford Fiesta which crashed at about 19:30 BST.
Thomas Quick, 18, from Clawddnewydd, and a 17-year-old boy from Dyffryn Clwyd, both pleaded guilty to death by dangerous driving at Mold Crown Court.
The defendants also pleaded guilty to four counts of causing serious injury by dangerous driving.
Quick was not directly involved in the collision, but was "repeatedly racing" with the 17-year-old driver, who cannot be named for legal reasons.
The 17-year-old's car crashed with another car coming in the opposite direction between Clawddnewydd and Ruthin, leaving the passengers of the other vehicle, Dylan Jones and his mother Anwen Jones, with serious injuries.
Judge Niclas Parry called for law changes for newly-qualified drivers to only be able to carry one passenger and have a monitoring box installed in the first year after passing their test.
"On 27 June last year, the life of one family was shattered beyond repair, the lives of four other people were, to varying degrees, changed for forever," he said.
He described the case as "one of the worst examples of dangerous driving one could imagine".
"You two were the cause of those dreadful consequences and that was purely due to your arrogance, selfishness and egotistical conduct," he added.
'Day of reckless driving'
The court heard the crash came on a "day of reckless driving" by the defendants who had "repeatedly used the roads of Denbighshire as a race track".
The 17-year-old driver of the car in which Olivia was a rear seat passenger had only passed his test the day before.
Both he and Quick drove to a stretch of road outside Llysfasi College to race each other on the afternoon of 27 June.
With their friends watching on, they raced side by side at high speed, with the younger newly qualified driver "winning on both occasions".
The court was told the younger driver had heard that day that his car was to be fitted with a black box the following day which would mean he couldn't drive at high speeds.
"It's clear he felt he had to take his chance to drive quickly" that day, said John Philpotts, prosecuting.
Footage shown to the court from another car heard friends saying "they are going to die... we are going to drive past a burning wreck... surely it will happen one day".
The crash happened that evening.
The court also heard Quick had been warned about his driving by teachers on several previous occasions in the weeks before the crash.
The two other teenage girls involved in the crash suffered several broken bones, and one needed surgery after rupturing her bowel in the crash.
In the oncoming car, Dylan Jones suffered extensive injuries to his lower leg, while his mother broke her wrist and a rib and needed more than one operation.
The court heard Mr Jones spent 54 days in hospital and both he and Ms Jones had to have their houses adapted before they could return home.
'Beautiful, kind and fun-loving'
Olivia was a "fun-loving, wise, ambitious individual" who was "loved by all who knew her", her family said in a statement last year.
She was a deputy head girl and A-level student at Brynhyfryd School, where she studied physics, mathematics, geography and the Welsh Baccalaureate.
Her family said she had hoped to go on to study architectural engineering at university.
Giving a victim impact statement in court, her mother, Jo Alkir, said Olivia was "beautiful, kind and fun-loving".
She listed all the things she and her husband "deserved" to experience with Olivia but would now miss out on - from the stress of helping her cope with her A-levels all the way through to her telling them at some point in the future she was pregnant with the first of the three children she dreamed of having.
She said "our grief is so overwhelming that all we can wish for is our own early death" to release them from their suffering.