EVALUATION OF IN-CAR COUNTERMEASURES TO SLEEPINESS - COLD-AIR AND RADIO

The efficacy of putative ''in-car'' countermeasures to driver sleepine ss is unknown. Sixteen young adult drivers within the normal range for the Epworth Sleepiness Scale (ESS), had their sleep restricted to 5 h ours the night before, and drove an interactive car simulator in the a fternoon for 2.5 hours, under monotonous conditions. After 30 minutes of driving they were exposed to: (1) cold air to the face (AIR) from t he vehicle's air conditioning vents, (2) listening to the vehicle's ra dio/tape (RADIO) according to subjects' choice, or (3) NIL treatment. The active treatments typified those experienced under real driving co nditions. Drifting over lane markings were ''incidents,'' EEGs were re corded and spectrally analyzed in the alpha and theta range. Subjects responded to the Karolinska Sleepiness Scale (KSS) every 200 seconds. Overall, RADIO and AIR had no significant effects on incidents, althou gh there was a trend for RADIO to reduce incidents, particularly durin g the first 30 minutes, when AIR also had some effect. KSS scores were significantly lower for RADIO for most of the drive, whereas AIR had only transient and non-significant effects. The EEG showed no signific ant effects of the active treatments. Compared with other countermeasu res such as caffeine and a brief nap, which we have previously shown t o be more effective (using the same equipment and protocols), AIR and RADIO are at best only temporary expedients to reduce driver sleepines s, perhaps enabling drivers to find a suitable place to stop, take a b reak and avail themselves of caffeine and a nap.