A drunk driver and three passengers died instantly when their car hit a tree and a granite gatepost at high speed.
Stefan-Marian Leonte was behind the wheel of the white Mercedes CLK when it crashed killing the 30-year-old, Andris Daukuls, 36, Alexandru Bogdan Chirita, 30, and 19-year-old Alexandru Bogdan Chirita.
The inquest heard Mr Leonte had 269mg/100ml of alcohol in his blood which is more than three times the UK legal drink-drive limit when the crash happened on the way from Bugle to St Austell.
Adrian Boca, who was the front passenger at the time, was the sole survivor of the crash on May 1.
He was able to escape the vehicle after it landed on its roof and flagged down another driver who drove him back to Bugle with a head injury, Cornwall Live reports.
In his evidence read out as part of a police statement Mr Boca said he only wanted to travel with Mr Leonte to ensure he would drive safely, as he knew he was already inebriated.
But the inquest heard how his and Mr Chirita's pleas for Mr Leonte to slow down and drive more safely fell on deaf ears.
The driver carried on driving erratically and faster and faster on the 40mph road.
In his statement, Mr Boca said: "Me and Alex shouted for him to stop and slow down but he didn't. It was the fastest I have ever travelled in a car. The car was weaving about then it rolled."
It was uncovered that the Mercedes also had an under-inflated rear tyre, because of an embedded nail.
This may have contributed to the car being more difficult to steer and control at high speed while drunk.
The inquest also heard that Mr Leonte's driving was so erratic that he drove on the wrong side of the road for long stretches during the journey in Bugle where the four men had met up that evening, and even went through a red light.
Mr Boca said he had hoped the red light would provide him with an opportunity to get out of the dangerous car had the driver stopped at the lights as he should have.
In his statement he said: "I thought he would stop so I'd get out. All along I kept asking him to stop. But he didn't. He was showing off."
PC Justin Heayn, from Devon and Cornwall Police's serious collision investigation team at Bodmin, led the investigation in the crash back in the spring.
He said the road had no defects, the weather had been fine and, despite the under-inflated tyre, no other defects were found on the car. He insisted that the slow puncture would not have been a contributing factor of the crash on its own.
All three men died at the scene from multiple head and neck injuries after it hit a tree, which snapped, and rolled onto its roof and hit a granite wall and gate post and demolished it. The three men's injuries were so serious they likely died instantly.
The inquest heard that while one of the passengers had not been wearing his seat belt, it was not possible to say whether the belts which were clicked in on the other casualties had actually been worn correctly because the car caught fire after rolling onto its roof.
Mr Boca had been wearing his seat belt at the time of the crash.
Adrian Roberts, from Cornwall Council highways contractor Cormac, confirmed to the inquest that the road had no defects and was considered a "benign bend" with adequate signage, chevrons and slow down markings on the road and speed limit signs.
He told the inquest that in the past five years there had been no accident on that stretch of road prior to this fatal crash.
In the past 10 years two other collisions had occurred, once when a biker had been drinking and another when a biker braked too hard and lost control.
Recording a cause of death as road traffic collision for all three men, assistant coroner for Cornwall and the Isles of Scilly, Guy Davies, said this case "showed the terrible consequences of drink driving".
He added: "This shows the lethal dangers for those who get into a car with a driver under the influence of alcohol. It shows how it may not be possible for passengers to persuade a drink driver to stop. Three people have lost their lives as a direct consequence of drink driving."
