Fatigue is a primary human factor for decreased job performance in the workplace. It is well documented that drowsiness is a typical symptom of fatigue and is closely associated with commercial drivers' safety and well-being. However, few studies have been conducted to develop or validate fatigue symptom instruments for a working population. The main purpose of this study was to develop a general fatigue checklist and a driving fatigue checklist for Korean commercial drivers.

A total of 287 bus drivers in a commercial transportation company participated in a self-administered survey that was designated Study 1. Based on the statistical results of Study 1, a focus meeting with 16 professional consultants was conducted to revise the fatigue symptom instrument for Study 2. In Study 2, 288 commercial drivers (156 bus drivers and 132 truck drivers) participated in the revised questionnaire survey. All collected responses were entered into a SPSS worksheet and the data analysis was conducted using SPSS software 11.1. The exploratory factor analysis used in this study followed the principle component factoring rule and the varimax rotation method for factor extraction. The criteria for item selection were an Eigen value of 1.0 or greater, a communality score of .50 or greater, and no ‘fence rider’ property over the extracted factors.

Through Study 1, the consultant meeting, and Study 2, a general fatigue checklist was developed with a total of 3 factors and 11 items, and a driving fatigue checklist was developed with 2 factors and 10 items. The 3 factors of the general fatigue checklist were physical fatigue, psychological fatigue, and chronic tiredness. The two factors of the driving fatigue checklist were physical fatigue and perceptive and functional fatigue.

The primary contents of general fatigue were different from those of driving fatigue according to the two fatigue instrument factors developed in this study. The primary fatigue symptoms of the commercial driving population were identified as physical fatigue and perceptive and functional fatigue.