Drivers Penny Ashton, Justine Smith, Ewen Gilmour and Cori Gonzalez-Macuer fuel up with help from barman Ben Quigan. Photo / Janna Dixon

Drivers Penny Ashton, Justine Smith, Ewen Gilmour and Cori Gonzalez-Macuer fuel up with help from barman Ben Quigan. Photo / Janna Dixon

Cori Gonzalez-Macuer, a skinny Chilean-New Zealand comic, is behind the wheel of a late-model BMW. He's been drinking. In an hour-and-a-half he has downed eight bottles of beer. He knows he's over the legal limit, but he presses the ignition button anyway.

"I'm feeling good," he says, his lithe 74kg frame showing little visible effect from his binge on Becks. Good enough to drive? "I think so. Well, I'm not okay to drive, but I'll think I'll do okay."

Ewen Gilmour, a Westie comedian, tries to intervene at the driver's side window: "Don't do it, mate. Don't do it."

But his friend won't be deterred: "Don't worry. I'm sweet, bro."

And, with a gun of the four-cylinder diesel engine and a heavy-metal track blaring on the stereo, Gonzalez-Macuer is off. Within a matter of seconds he is pushing corners hard and rocketing along at 80km/h. But when the road narrows, the vehicle veers a little to the left and gets close to the edge. Too close. There's a thud, and Gonzalez-Macuer has officially left the road.

Fortunately this drive, run under controlled conditions at Pukekohe Park racetrack by BMW Advanced Driver Training, has only killed eight road cones.

"That's a full strike," says BMW's Mike Eady of the now-scattered row of orange markers.

As Gonzalez-Macuer parks the car clumsily at the end of his test, Eady shakes his head at the driver's drunken performance. "He had more hits than Michael Jackson."

On Wednesday, on a sunny afternoon south of Auckland, Gilmour and Gonzalez-Macuer were joined by fellow comics Penny Ashton and Justine Smith for a Herald on Sunday special investigation into the effects of drink-driving.

This was no laughing matter. The findings - about the effects of alcohol on driving ability and the amount New Zealanders are legally allowed to drink before getting behind the wheel - are shocking and will make sobering reading for the public and the two government agencies which manage the tricky legal relationship between automobiles and alcohol.

According to a speech given by Transport Minister Steven Joyce this month, and starkly confirmed by this experiment, you can drink the better part of a bottle of wine or a six-pack of beer in a mere 90 minutes and still be legally - if not practically - safe to drive.

The Law Commission and the Ministry of Transport are looking at the cost of drink-driving and what can be done to reduce it. Alcohol-related crashes killed 119 people last year, a figure that has plateaued since major improvements were made in road safety the early 1990s.