2.4 Recognising and Managing Fatigue
Key Takeaways
Warning signs include repeated yawning, heavy eyelids, drifting, missed signs and difficulty remembering the recent road.
Sleep loss, time of day, long duties, monotonous travel and untreated sleep problems can combine to increase fatigue.
If fatigued, stop safely and arrange rest or another driver; legal work-hour allowance does not authorise fatigued driving.
Recognise the warning before a microsleep
Fatigue reduces alertness and the ability to maintain attention. It can slow reactions, narrow observation and impair judgement before the driver recognises serious sleepiness. A microsleep is a brief involuntary sleep episode. During it, the vehicle continues moving while the driver cannot reliably observe or respond.
Do not wait for a microsleep to prove that a stop is necessary. Warning signs include heavy eyelids, repeated yawning, difficulty focusing, drifting within the lane, inconsistent speed, missing signs or exits, and being unable to remember the recent stretch of road. Irritability and difficulty making ordinary decisions can also be clues. Several signs together require action, not a more determined effort to stay awake.
Why fatigue develops
The need for sleep builds with time awake and inadequate previous sleep. The body’s daily rhythm also changes alertness across the day, with particular risk during normal sleeping hours. Long or irregular duties, night work, monotonous roads, poorly timed breaks, illness and sleep disorders can combine. A driver may start a shift already sleep-deprived; fatigue is not measured only from the time the vehicle left the depot.
| Risk factor | How it appears in a duty | Better planning response |
|---|---|---|
| Inadequate sleep before work | Early start after a late night | Delay or replace the driving duty |
| Night or irregular work | Driving through normal sleeping hours | Protect sleep opportunity and plan appropriate rest |
| Long loading delay | Waiting becomes active work or extends the duty | Recheck the schedule and legal hours |
| Monotonous travel | Attention drops on a familiar highway | Plan stops before warning signs escalate |
| Persistent daytime sleepiness | Repeated sleepiness despite sleep opportunity | Obtain medical assessment |
Workload matters even when the wheels are not turning. Loading, paperwork, inspections and other vehicle-related tasks can count as work for fatigue regulation. Physically demanding tasks can also increase tiredness. A schedule that counts only driving time may both miscalculate legal hours and underestimate the driver’s actual fatigue.
Distance during a lapse
At 100 km/h, the vehicle travels approximately 27.8 metres each second. In a four-second lapse it travels about 111 metres: 100 divided by 3.6, multiplied by four. This is a simple distance illustration, not a claim that every microsleep lasts four seconds. It shows why even a brief loss of attention can carry a truck through a bend, queue or roadworks before any corrective action.
The risk is not limited to high-speed roads. A momentary lapse while reversing can put a pedestrian behind the vehicle in danger. At an intersection it can cause the driver to miss a signal or start moving before the trailer path is clear. Fatigue controls therefore apply across the entire transport task, including yard movements.
Respond while a safe option remains
When warning signs develop, reduce exposure by finding a safe stopping place and stopping. Do not brake abruptly in a live lane unless an immediate emergency requires it. A suitable truck rest area or other lawful location should provide room to park without obstructing traffic and allow the driver to rest safely. Notify the operator and revise the duty rather than treating the delivery time as fixed.
Opening a window, loud music, conversation and fresh air do not cure fatigue. Caffeine may temporarily affect alertness but does not replace sleep or make a fatigued driver safe for a guaranteed further period. A short nap can help with acute sleepiness, yet a driver still needs to reassess fitness after waking and allow any grogginess to settle. It cannot erase accumulated sleep loss or override a required major rest break.
Plan sleep as part of the job
Protect adequate sleep opportunity before the duty and during time off. Consider commuting, meals, family responsibilities and accommodation: a nominal rest period may leave much less time for sleep. A quiet, suitable sleeping environment matters. Discuss a roster that repeatedly leaves you sleepy with the operator, and seek assessment for persistent symptoms such as severe daytime sleepiness or suspected sleep apnoea.
A useful trip plan identifies stopping places, expected driving and other work, foreseeable delays, and what to do when the schedule changes. If unloading takes two hours longer than planned, recalculate the remaining duty before leaving. Do not compensate by speeding or omitting breaks. Dispatchers and customers should have realistic expectations that permit lawful, safe completion.
Compliance is a floor
The work-and-rest table sets legal limits; it does not measure the individual’s alertness. A driver can be fatigued within those limits after poor sleep or illness. Conversely, feeling alert does not permit exceeding the limits. Both tests matter: lawful hours and actual fitness.
Key decisions
Recognise early signs, stop safely, protect sleep and revise the schedule. Treat fatigue as a changing condition throughout the duty rather than a box checked once at departure.
Official sources
Official handbook, health and safety; NHVR fatigue management. Sources checked 10 October 2026.
A driver has legal work hours remaining but is yawning repeatedly and drifting toward the edge line. What should they do?
Keep driving until the legal limit is reached
Open the window and guarantee another hour of driving
Increase speed to finish before becoming more tired
Stop at a safe place, report the problem and arrange appropriate rest or another driver
Sections you finish are checked off in the contents.