Background: Driving performance is influenced by human, vehicular, and environmental factors. Objectives: To investigate the effects of distraction tasks, such as sending a text message (STM) and searching a navigation device (SN), on the driving performance of experienced taxi drivers. Methods: Twelve male taxi drivers (age: 56.3 ± 4.4 y; experience: 28.4 ± 6.4 y) and 14 female taxi drivers (age: 55.5 ± 3.5 y; experience: 19.4 ± 5.0 y) drove in a simulator at a constant speed (90 km/h) for 2 min while maintaining a gap of 30 m from the car in front, also traveling at 90 km/h. Participants were instructed to drive only for the first 1 min (control phase). For an additional 1 min (task phase), they were instructed to drive only, drive + STM, or drive + SN. Results: Compared with driving only, during driving + STM or driving + SN, the drivers' skin conductance level was relatively increased, suggesting that the distraction task increased the drivers' workload and sympathetic nervous system activity. Compared with driving only, during driving + STM or driving + SN, the average distance from the car in front, speed deviation, and anterior-posterior and medial-lateral coefficients of variation increased, suggesting that maintaining the instructed gap and speed, and the longitudinal and transverse control of the car, was more difficult because of the distraction task. Conclusions: Even for highly experienced taxi drivers, distraction tasks increased workload, increased the difficulty of vehicle control, and detracted from safe driving.

This study was aimed to find out whether there was some difference comparing driving performance and the autonomic nervous system between normal state and sleep deprivation state, between sleep deprivation state and 100% Lavender oil exposed state and between sleep deprivation State and 100% Peppermint oil exposed state, while driving in a driving environment using a driving simulator. The subjects were 10 male drivers between 20 and 45 years age whose age in average was 30.9±7.7 years and who had been driving for 7±6.6 years, the road situation of three-lane road was copied as a driving environment, and the subjects were instructed to keep 1st lane, to keep a constant speed of 110km/h. In this driving condition, the subjects were instructed to steps on the brake until the speed of car is 0km/h, according to "STOP" sign shows in red which displayed on the screen suddenly. As a result of analyzing the reaction distance, there was a significant difference (p<0.05) between normal state and sleep deprivation state. Also, as a result of analyzing the speed average, there was no significant difference all groups. As a result of analyzing the LF/HF ratio, there was no significant difference before and after in all groups. As a result of analyzing the LF/HF ratio after unexpected situation, there was a significant difference (p<0.1) between sleep deprivation state and peppermint state. The results suggest that it could be judged that expressway accidents at 0 a.m.-6 a.m. are closely related to drowsy driving. This phenomenon is thought monotonous driving environment and lack of sleep is coupled to lower the driving performance, and the peppermint has a statistically significant difference on the change in driving performance comparing sleep deprivation, such as the reaction distance. this means that the odor may be possible to temporarily driving performance improve.

This study aimed to find out whether the reading fatigue by an e-book can be relieved through the stimulation of Lavender odor which has a relaxing effect. The experiment was conducted the subjects of 15 men and women in their twenties who had no olfactory disorders, Photoplethysmography(PPG) was measured for the fatigue, and the subjective assessment was conducted for the subjective fatigue. As the result of the experiment, the fatigue was lower when e-books were read in the condition where Lavender odor was presented than when only e-books on a smart phone were read, where there was a significant difference(p<0.1). Therefore, as the result of the experiment in this study, given the effect of Lavender odor, the structure of a brain, and the cerebral acting region of sight and smell of the previous studies comprehensively, it is supposed that the increase in visual fatigue due to e-book reading outpaces the relaxing effect of Lavender odor which is absorbed through smell. It is judged that there should be many studies on the interaction on the cerebral capacity of sight and smell in the future.