Statistical study of tram driver accidents

This statistical study considers two basic hypotheses on industrial and traffic accidents the accident proneness theory and the spell theory. The two hypotheses were tested on the basis of a correlation analysis of accident distribution in a group of tram drivers over a five year observation period. Using the chi-square goodness of the test. the analysis showed the negative binomial distribution and the “short” distribution were successfully fitted,while the Poisson distribution significantly differed from the observations. Correlation analysis showed a significant correlation between the number of tram driver accidents over different periods, and that this correlation. although decreasing with an increase of the interval between observation periods, remained significant. The conclusion is that the proneness hypothesis explains more satisfactorily than the spell hypothesis the occurrence of accidents in tram drivers during tlie observation period.