This study surveyed 253 truck drivers and found that many drivers scored poorly on the Stanford and Epworth sleepiness scales indicating that they may not be as alert as they should be while driving. Moreover, those who rated the air in their truck cabins as fresh reported less irritation to their eyes, noses, throats, and skin, scored better in both sleepiness scales, and reported fewer sleep-related medical symptoms. Finally, the results of the ordinal logistic model indicate that drivers' perceptions of the air quality in their truck cabins are significantly related to their alertness during a trip.
