Abstract
The results of several studies are reported in which the influence of working hours on the risk of accident was investigated. Data were collected by means of a survey on the work-rest schedule of 139 truck drivers (totalling 1459 days of work). From this, it was possible to derive two "relative exposure indices" concerned with the amplitude of the work day, and one in relation to the time of day when the work is performed. Other data were extracted from accident reports.