In less than a kilometre an alleged drunk driver swerved across the road, straddled the centre line and drove up a roadside bank before a concerned motorist forced him off the road.
While Whangarei police don't encourage motorists to take matters into their own hands, they praised a light-truck driver who was concerned enough about the safety of other road users to act.
The chain of events began when a 71-year-old man pulled out of a State Highway 1/Otaika Rd property and headed north, about 8.10pm on Tuesday.
After passing through the intersection with Maunu Rd, the man's vehicle allegedly straddled the centre line of the two northbound lanes.
After driving over the brow of a hill, the driver veered to the left and drove up on to a bank before returning to the road and slowing to about 20km/h, police say.
People in a following car had phoned police while the driver of a light truck pulled ahead of the allegedly drunk driver and forced him off the road.
Whangarei police Strategic Traffic Unit Sergeant Graham Pugh said the man had travelled less than a kilometre before he was forced to stop.
"In some cases, particularly involving high speed, it is not appropriate for other drivers to intervene.
"But in this case and these circumstances the light-truck driver took the appropriate action and I commend him for it," Mr Pugh said.
At the Whangarei Police Station the suspect driver was breath-tested and recorded a breath-alcohol level of 790 micrograms of alcohol per litre of breath - nearly double the 400mcg legal limit for drivers aged 20 and over.