Abstract
Twenty seven professional truck drivers completed a 12 hour, 900 km trip under each of three driving regimes - a relay (staged) trip, a working hours regulated one-way (single) trip, and a one-way (flexible) trip with no working hours constraints. The results indicated that none of the driving regimes prevented fatigue and that the pattern of fatigue experienced during the trips appeared to be related to pretrip fatigue levels. (Author/publisher).