The men - Hawke's Bay farmhands Lou Wesley, 47, Jack Huata, 64, James Raupita, 42, and Paul Parata, 48 - were found covered in frost in a paddock off Waikare Rd at Putorino on the morning of June 3.
The had spent the night before drinking their way through at least two boxes of beers at a friend's place before heading home about midnight.
As the only passenger not thrown from the vehicle was in the back, police had to rely on injury analysis to establish who was driving.
Coroner Christopher Devonport, in findings published today, ruled Mr Huata was the driver, given he was the only person to have suffered chest injuries consistent with damage to the steering wheel.
Mr Huata had the lowest blood-alcohol level of the four men but it was still in excess of the legal limit.
Mr Huata's blood alcohol level was 114 milligrams of alcohol per 100 millilitres of breath. The legal limit for an adult is 80mg.
Tests also indicated he had possibly been using cannabis.
The four men were driving Mr Wesley's Mitsubishi Pajero towards Moeangiangi sheep station when it crashed on the unlit gravel road.
The vehicle was calculated to be travelling about 84km/h when it slid off a straight section of the road and rolled onto its left side as the front wheel dropped into a 50cm-deep furrow.
The Pajero's roof was ripped off as the vehicle crashed into a large tree and spun 180 degrees before it came to rest on its wheels.
Three of the men were flung from the vehicle, which only had seat belts for the driver and front-seat passenger.
There were no seats in the back and subsequently no seatbelts.
Senior Constable Cory Ubels, investigating the crash, said the driver "was not likely to have been applying the brakes at the time of the crash".
The Mitsubishi had an expired warrant of fitness and faults that may have contributed to the crash, the coroner found.
There was excessive play in the steering box, the front tyres were below legal tread depth and the right-hand ball joint was worn.
Mr Ubels said the vehicle was "likely to have been in an unsafe condition immediately prior to the crash".
Most significant was the steering box issues, which would have made it "very difficult to control the vehicle", Mr Ubels said.
Alcohol, speed and the lack of seatbelts were also responsible for another horrific crash in rural Hawkes Bay in January in which five members of a shearing gang were killed.
The five farmworkers were "wasted" when their car smashed into a truck at about 150km/h on State Highway 2 near Raupunga, a coroner was told.
- Kieran Campbell of APNZ
