Fatigue on a night line-haul with a delayed start
Mei is a line-haul driver scheduled to start a 10-hour shift at 22:00. She woke at 06:00, did household errands, and had a two-hour nap from 14:00 to 16:00. At 21:00 her dispatcher calls: the load is delayed and she must now start at 01:00, but the shift still ends at 08:00. Mei has already been awake since 06:00 apart from the nap. She drinks a double espresso at 21:30 and plans to 'rest in the cab' from 22:00 to 00:30. She has a 500 km run with one mandatory rest break. She feels alert after the coffee and considers skipping the cab rest.
1. Assess Mei's fatigue risk at the 01:00 start and explain whether the espresso and cab rest plan is sound.
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Mei's risk is high. By 01:00 she will have been awake for 19 hours apart from a two-hour nap, and the delay pushes her into the circadian low period when alertness naturally drops. The espresso at 21:30 may mask fatigue for a few hours but does not remove it; caffeine has a half-life of several hours and can also interfere with the cab rest she needs. A 22:00 to 00:30 cab rest is a sensible plan, but only if she actually rests and does not treat the coffee as a substitute. Skipping the rest because she feels alert is the key error: subjective alertness is a poor guide when caffeine and anticipation are present. She should take the rest, and if she cannot, she should not start the shift.
2. What should Mei do if she begins to feel drowsy at 03:30, and what does the fatigue rule require of her and her dispatcher?
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If Mei feels drowsy at 03:30 she must not push on. The safe response is to stop at the first safe place, take a break, and if necessary take a short sleep rather than relying on more caffeine or an open window. Continuing while drowsy is a serious risk on a night line-haul. Under fatigue management requirements, she must comply with her work and rest limits and record her hours; the dispatcher's late change of start time must be managed so the shift does not breach those limits or leave her without adequate rest. Mei should report the drowsiness and the changed start time, and the dispatcher should adjust the schedule. If the revised plan cannot be completed within the rules, the load should be delayed rather than the driver pressured.