Feeling awake doesn't mean you're safe to drive: what every fleet operator should know about fatigue

By Katrina Aubrey, Fatigue & Sleep Health Specialist, AutoSense

You can be an experienced, safety-conscious driver and still make a dangerous mistake when you're tired. Fatigue doesn't discriminate, and one of the biggest challenges is that we aren't always good at recognising when it's affecting us.

We've all had nights when we haven't slept well. Perhaps we've gone to bed too late, had children keeping us awake or simply woken feeling like we need another few hours. Most of us get up and carry on. But being awake doesn't automatically mean we're functioning at our best.

I describe fatigue as your brain and body running on a low battery. You can still function, but everything requires more effort. Fatigue and sleepiness are not quite the same thing, but both can affect driving safety. Your attention, decision-making and reaction times suffer, even if you don't necessarily feel sleepy.

Research has shown that after approximately 17 hours of continuous wakefulness, impairment on certain performance tasks can be comparable to that seen with a blood alcohol concentration of 0.05%. We understand alcohol impairment. We have legal limits and breath testing, and wouldn't accept someone driving a heavy vehicle while intoxicated. Yet when someone says, "I'm tired, but I'm fine", we're much more likely to accept it.

Fatigue is biological, not a choice

Two biological processes largely determine how alert we feel. The first is our circadian rhythm, or body clock, which naturally promotes wakefulness during the day and sleep at night. Between approximately 2am and 6am, our drive for sleep is particularly strong.

The second is sleep pressure, which builds from the moment we wake. The longer we're awake, the greater our need for sleep. The only way to properly clear that pressure is through sleep itself.

Now imagine those two processes coming together at 4am. Your body clock is pushing you towards sleep, your sleep pressure is high, yet you're expected to operate a heavy vehicle, make decisions and remain attentive.

For transport operators, understanding this biology is critical. Fatigue isn't simply a matter of drivers taking responsibility and getting more sleep. Shift patterns, long working hours, recovery opportunities and underlying health conditions all influence how alert someone is behind the wheel.

Eight hours in bed doesn't always mean eight hours of quality sleep

One of the most important things I've learnt working with commercial drivers across Australia and New Zealand is that fatigue can have underlying causes that aren't immediately obvious.

Through my work with AutoSense, a fleet and driver safety provider combining in-vehicle monitoring technology, fleet training and advisory and expert guidance on sleep health, I help businesses understand why fatigue events occur and how they can better support their drivers.

There are more than 80 recognised sleep disorders, including insomnia, restless legs syndrome and obstructive sleep apnoea. 

Sleep apnoea is particularly relevant in the transport industry. It causes repeated interruptions to breathing during sleep, often without the person realising. Some people wake feeling exhausted despite spending eight hours in bed, while others may have significant sleep apnoea without recognising any obvious symptoms. 

One saying I regularly use is, "Do not ignore the snore." Loud, persistent snoring, particularly when accompanied by pauses in breathing, is worth investigating with a GP or sleep specialist.

If a driver is repeatedly fatigued despite apparently getting enough sleep, we need to be curious rather than judgemental. Could something else be going on?

Small changes can make a big difference

There are also practical steps drivers can take to protect their sleep.

Adults generally need seven to nine hours of quality sleep each day. Creating a cool, dark and quiet sleeping environment is particularly important for shift workers who need to sleep during daylight hours.

Caffeine and alcohol consumption, particularly close to bedtime, can interfere with our sleep quality. Reducing screen time and bright light before bed also gives the brain an opportunity to wind down, while getting natural light after waking helps regulate our body clock.

But what happens when fatigue strikes during a shift? Sleep-related fatigue can result from insufficient or poor-quality sleep, extended wakefulness or disruption to our body clock. Task-related fatigue can develop during prolonged or repetitive activities, such as monotonous driving, where reduced stimulation can also make existing sleepiness more noticeable. 

A short nap or caffeine may temporarily improve alertness, while moving around or changing tasks can help counter monotony. However, these are temporary countermeasures, not substitutes for adequate sleep. If a driver becomes sleepy behind the wheel, the safest action is to stop driving in a safe location and take appropriate rest before continuing. 

Better fatigue management starts with better conversations

For fleet operators, effective fatigue management means looking beyond individual events to understand the contributing factors. Are work schedules providing adequate opportunities for sleep and recovery? Could an untreated sleep disorder be involved? Do drivers feel comfortable reporting fatigue without fear of judgement?

In-vehicle monitoring technology goes a long way to help identify signs of drowsiness and potential fatigue risk, but understanding why an event occurred is just as important as detecting it. Ultimately, the sleep we get tonight influences the brain we bring to work tomorrow. It determines how well we concentrate, react and make decisions. And in an industry where a momentary lapse can have devastating consequences, one of the most important safety systems we have is an alert brain.

Find out more about AutoSense and its fatigue management solutions here.