A trial on some Auckland buses has found drivers falling asleep at the wheel and an "undeniable" risk of fatigue.
Autosense has camera units that pick up someone asleep for 1.5 seconds or more - the units then shake the seat to wake them.
Chief executive Charles Dawson said the company was seeing an increase in cases of 'micro-sleeps'.
"For the 5000 Guardian units that we have installed around New Zealand in light and heavy vehicles, there has been 30 percent more micro-sleep events per kilometre driven" between 2021 and 2022, he said.
"We're seeing on average at this point in time around about 150 micro-sleep events per day."
Official figures show in 2020 and 2021, 25 people died in road crashes where fatigue was identified as playing a part; in 2021, 92 were seriously injured.
Autosense only monitors commercial vehicles - trucks, buses, company cars - but Dawson believes other drivers were falling asleep just as much.
"Yeah, look, really scary. I think one of the big things that we see out there is luck," he said.
"Most times when you fall asleep, you might hopefully wake up before a corner comes or the car drifts across the centre line."
The recordings showed the times people most often fell asleep were 5am and 11am, and that it was at least as bad on urban roads as on the open road.
The Auckland bus driver trial in 2021 detected 11 driver micro-sleeps on 20 buses in two months.
The first lot of bus results came in at 10 times the company's national average for micro-sleeps, Dawson said.
"They are obviously getting getting less sleep than everyone else."
NZI sponsored the Auckland Transport bus trial with an unnamed bus company. A trial report RNZ recently obtained shows this was prompted by claims of fatigue.
"Doing nothing is not an option due to the known existence of a significant fatigue risk which may cause harm to drivers, passengers or other road users," the report concluded.
Auckland Transport on Wednesday said it was continuing to work with bus operators, 15 months on from the trial, to "ensure they have robust fatigue management practices in place and to support them as they explore different technology options".
Sleep researcher professor Leigh Signal warned against relying too much on the technology.
"I see it happening time and time again in different organisations," she said.
"They choose a technology solution and they think they've ticked that box, where there's so many upstream actions that need to be around it.
"[But] I can see from that trial that there are other great things that they were trying to put in place."
Auckland Transport metro services manager Darek Koper said it was looking at the underlying causes, as well as working with Waka Kotahi to change bus specifications so new ones would have electronic systems that supported fatigue management.
Official statistics suggest driver fatigue was dropping not rising.
All the trend lines tend to rise, up until around the year 2000, then drop from then, including for deaths and serious injuries in the past three years.
But Signal said driver fatigue was tricky to gauge, and she believed it was most likely stable or rising.
"It is often not recognised and it tends to be under reported.
"So my concern is that what we're actually seeing in the national stats is just the tip of the iceberg."
In the Auckland bus trial, many drivers resisted the monitoring, some going as far as ripping out the camera units, or shifting the camera so it could not see them yawning.
"With the high number of camera misalignment issues and cameras being covered by drivers, it is likely to mean that the true number of fatigue events ... were not discovered," the report said.
Communicating with drivers was vital - many had English as a second language - and should be done in company time, it said.
First union researcher Edward Miller echoed that, and said the Auckland Transport trial came at a time of fraught worker relations with the bus companies, which would not have helped.
"New life-saving tech is extremely valuable in terms of improving worker safety outcomes, but you have to bring your workers along for the ride," Miller said.
"That's what your health and safety reps are for - to make sure there's no trade off between implementing safety measures and maintaining decent working conditions."
WorkSafe said ultimately Auckland Transport held the primary duty of care on fatigue management for its drivers, and it expected it to take steps.
Among the truckers that were using the seat shaking units was Dynes, based in Otago.
It declined to comment but on its website said the cameras mounted on the dash were sensitive, "monitoring eyelid droop and if the driver's eyes close for a longer period than a blink".
"For example, if the driver's eyes close, or their head drops, the system loses its eye lock and then issues a critical and loud verbal alert."
It also had a staffer back at base who saw the alerts and could contact the driver.
Dawson said it was simple.
"I'll often say to to drivers, you know, if I'm coming the other way, and I've had a very bad night's sleep because I've got a new baby in the house or something along those lines, and I fall asleep, would you rather I'm woken up or would you rather I come across that centre line?"