An ex-cop is looking at the effects kava can have on driving, by testing neurological function after kava drinking sessions.
It's a drug but not linked to harmful effects like alcohol is. But there's little science around kava, intoxication and driving.
A new study is aiming to establish whether there are detrimental effects. It's the work of Waikato University researcher Apo Aporosa.
The research was funded by the Health Research Council.
Aporosa estimates 20,000 New Zealanders consume the Pacific beverage, with no clear evidence of the impact it may have on the roads.
Twenty participants were asked to drink 3.6 litres of kava over six hours.
Their neurological function was then tested to measure focus, accuracy, timing perception and fatigue. None of these were affected in a significant way.
But one really important function was negatively affected - temporal order judgement. It's related to how you make sequencing decisions, for example, deciding what to do when approaching an intersection.
"My advice for drivers is, could my kava drinking endanger my passengers or other road users, because if it could then that's not respect, and it's not what kava stands for or our Pacific values," Aporosa said.
Police have welcomed the study and their advice remains that you shouldn't drive while under the influence of any drug.