Northland's Coffee Brake campaign has been successful in keeping fatigued drivers off the road, a Whangarei district councillor says.
John Williamson, who chairs Roadsafe Northland, said the offer of a free coffee by 23 Northland cafes had helped get tired drivers off the road and prevent crashes.
"It's about encouraging people to recognise that taking a break while driving is a good thing to do."
Canterbury University researchers are developing a device which detects drowsiness and could help prevent fatigue-related crashes.
Thirty-one people died on New Zealand roads in fatigue-related crashes in the year to February 2012.
Mr Williamson said fatigue had been a significant problem on Northland roads, although it was starting to reduce.
"But I think overall on roads throughout the country, fatigue is a bigger problem than most people acknowledge."
International studies indicated that up to 30 per cent of crashes were due to fatigue, Mr Williamson said.
An Australian study of short-haul day-shift drivers found 45 per cent of drivers reported "nodding off" while driving in the previous 12 months.
A fatigue-detecting head-mounted prototype, dubbed a "world first", is being developed by electrical engineering PhD student Simon Knopp.
"Lapses can have serious consequences. Truck drivers, pilots, and air traffic controllers, for instance, have to stay alert for long periods of time and risk causing fatalities if they don't."
Mr Knopp's device detects such lapses and alerts a person before they have an accident.
Multiple sensors are used to determine the person's state.
A miniature camera looks at the eyes, and sensors measure brain activity and head movement.
"[Lapses] vary from micro-sleeps, where you essentially fall asleep for a moment, to sustained-attention lapses.
"Most people have these lapses and often aren't aware they're having them."
AA Road Safety spokesman Mike Noon said crashes caused by fatigue happened regularly, both in cities and on long journeys.
But it was difficult to determine if somebody crashed because they were tired, inattentive, or had fallen asleep.
Some car manufacturers are already introducing systems that attempt to monitor driver drowsiness, Mr Knopp said.