“…Since it was our opinion that the human element was the most important etiologic factor in the high incidence of accidents, we decided that the best method of reducing the number of accidents was to emphasize the selection of the operator, with particular stress on the medical and mental problems involved. In order to accomplish this, three major steps were taken: (1) The establishment of rigid preplacement examinations as part of an improved driver-selection program, (2) the institution of periodic medical examinations of operators, and (3) the creation of a comprehensive medical program for employees. Details of our studies have been reported elsewhere [2].…”