She wanted to get home for the New Year and sought to avoid the traffic. Home was 400km away and she had finished her day's work by 5.30pm. She had a rest and a meal and set off by herself at 8pm.
She called on friends a couple of hours later and they urged her to stay the night. She said that she was fine and carried on. Another couple of hours and she had another break, texted her family and set off again.
• Driver fatigue monitoring cameras to be installed in 4000 trucks
• Ministries need policies to prevent driver fatigue, coroner finds
• Premium - John Williamson: Truck driver fatigue and adequate rest areas in spotlight at NZTA Northland workshop
An hour later, she went to sleep and did not wake up. The clock said 1.30am, the speedometer read 95km/h. There was no sign of a crash, no skid marks, no crash debris. She drove straight off a corner of the state highway and into a tree below the road.
A passenger on a bus spotted the car next morning and alerted the driver. She was found at 9am with her seat belt on and hardly a scratch. She had died from a traumatic brain injury and literally appeared to be asleep at the wheel - she was 50km from home.
Many of us are prone to microsleeps while driving and crashes involving fatigued driving are more common than the statistics acknowledge. A number of research studies suggest that up to 60 per cent of us admit to driving while drowsy with around a third of us acknowledging falling asleep behind the wheel at some stage.
One laboratory study at Christchurch's neurotechnology research programme had subjects doing visual tracking testing. This involved using a joystick to continuously follow a target on a monitor while their brain activity and eye movements were recorded.
The study found that 80 per cent of subjects had microsleeps with an average of 39 over an hour period with an average duration of 3.4 seconds.
This was a laboratory experiment and does not necessarily mean that many of us are asleep at least part of the time behind the wheel. What it suggests is that most of us have the propensity to switch off momentarily when engaged in monotonous or repetitive activity.
If you are driving alone at a time when you would normally be sleeping, you are particularly at risk.
When driving with others we are continually reminded about our physical needs. Children, in particular, remind us when we need a break and the front seat passenger is often keeping an eye on the road, the speedo or watching how the driver behaves.
The front seat passenger may also moderate the level of conversation according to the challenges of the driving task. A well aware family group tends to manage itself.
When we are driving alone we can become distracted or preoccupied and nobody tells us when our driving behaviour is off track. You are in danger if:
• You feel your head nod down and jerk up or are continually yawning.
• You become aware that you've moved unintentionally in your lane or unintentionally changed speed.
• You know you are on a familiar route, but don't remember passing particular places
• You realise, with a start, that you need to brake heavily to avoid a hazard.
These danger signs mean that you've been asleep at the wheel. In those 3-4 seconds when you were asleep you can travel the length of a rugby field. That's when drivers run off the road into a tree and there's no sign of braking to avoid it.
If you pick up the signs of getting drowsy, the best thing you can do is stop driving. Pull over safely off the road, get out, walk around, have a cup of coffee and re-orient yourself. Ideally have a short 15 minute power nap.
Your body is telling you it needs a rest and the logical, sensible and safe thing to do is for your brain to tell you to have one.
• John Williamson is chairman of Roadsafe Northland and Northland Road Safety Trust, a former national councillor for NZ Automobile Association and former Whangārei District Council member.