The level of alertness is regulated and influenced by factors associated with sleep, diurnal rhythms, time factors and a number of individual and environmental parameters. Environmental factors with an effect on wakefulness and drowsiness are sound, temperature, light, vibration, ventilation, ergonomics, physical activity and nutritional intakes. According to the results from a laboratory study where different degrees of temperature reduction, duration and interval were tested, temperature regulations can be applied as a method against driver fatigue. By use of these findings, a system based on four to eight minute periodical reductions of the cabin temperature was designed. The intervals between the five and ten degree cooling periods varied between five and eight minutes. Use of the system resulted in a consistently positive effect on driver alertness. Design for autoimmunisation of the vehicle cabin temperature might thus be a successful method for the maintenance of driver alertness.
Samenvatting