The Effectiveness of In-vehicle Peppermint Fragrance to Maintain Car Driver's Alertness

The numbers of the traffic accidents related to human factors are increasing rapidly. Among all contributing factors to the accident, fatigue and sleepiness on wheel are the most common reasons. Both conditions decrease drivers’ alertness, resulting in performance decrement and accident risk increment. The alertness degradation is usually not well recognized by the drivers. Peppermint fragrance is commonly known on its freshness as medicine or aromatherapy. This research was conducted to examine the effectiveness of peppermint as a car freshener in order to maintain drivers’ alertness level. A within-subject design experiment was carried out in a car-driving simulator laboratory engaging twelve male participants. There were two driving conditions: with placebo and with peppermint fragrance. Placebo and peppermint fragrance was released continuously using an electric vaporizer. The participants’ alertness level was monitored via brainwave activities using electroencephalograph (EEG) along 30 minutes of driving. Frequency analysis on EEG data was conducted to determine the alpha, theta, and beta power band on F3 and F4 of lobus frontal to generate the (α+θ)/β ratio. Results of this study demonstrated that the application of the peppermint car freshener resulted in lower slope of (α+θ)/β ratio rather than placebo condition (0.018 vs. 0.026), though the difference was not significant (p = 0.216). The results suggest that the peppermint is promising to be applied as in-vehicle fragrance in order to maintain drivers’ alertness. Further research can be conducted to test various method of fragrance exposure to get more substantial increase of alertness level.