Fatigue causes an estimated 20–30% of serious road collisions in Sweden. A driver who has been awake for 18 hours has impairment equivalent to a BAC of 0.5‰ — yet most fatigued drivers believe they are still capable.
Warning Signs of Fatigue
Yawning repeatedly, heavy eyelids, drifting between lanes, missing road signs you just passed, slowed reaction time, and microsleeps (involuntary sleep lasting 1–30 seconds) are all danger signals. If you experience any of these, you must stop as soon as it is safe to do so.
Microsleep
A 4-second microsleep at 100 km/h means your vehicle travels 111 metres completely uncontrolled. Most occur without the driver being aware they happened. There is no reliable way to detect them in yourself until it is too late.
Managing Fatigue
The only cure for fatigue is sleep. Caffeine and energy drinks delay the worst effects for 20–30 minutes but do not restore driving ability. If you are tired, stop at a service area and sleep for at least 20 minutes before continuing.
Exam tip: Opening a window or turning up music does not prevent microsleep. The theory test may ask about fatigue countermeasures — only stopping and resting is correct.