Sound exposure as a measure against driver drowsiness

Twelve lorry drivers participated in a field study, including in total 110 tests of a waking sound system. The system was based on a time and frequenc y varied sound, generated at intervals between 1 and 15 min for periods of 3-7 s. The waking effect of the sound was analysed through subjective ratin gs. Exposure to the sounds was correlated to improvements of the immediate as well as the longterm self-reported changes in wakefulness. The results o f the study show consistently positive assessments concerning the applied w aking system, both regarding the system as a measure for raised wakefulness , increased road safety and the interest in having the system installed in the vehicle. The waking sounds were in no case felt to be annoying. Analyse s of the wakefulness and other factors and the interaction related to fatig ue and driving are included in the investigation.