Comparison of self-reported and observed prevalence of safety belt and helmet use in Florence

METHODS: Safety belt and helmet use was estimated from PASSI data and measured through Ulisse observations. Between 2008 and 2012 a total of 2,081 cars and motorcycle users were interviewed in the LHU of Florence and a total of 59,787 drivers (11,870 front passengers, 1,129 rear passengers and 16,816 motorcyclists) were observed. The comparison between self-reported and observed prevalences was performed by calculating the over-reporting factor (ORF), defined as the ratio of the self-reported to the observed prevalence of seat belt or helmet use. The time trend of the prevalence (both from self-reported and observed data) and of the ORF was assessed by using linear regression and Poisson's regression, respectively. RESULTS: The correlation between self-reported and observed prevalence is high, with a Pearson's correlation coefficient of 0.95 (p CONCLUSIONS: The reasonable accuracy of self-reported data makes this method fit in the routinary assessment of safety belts and helmet usage, in order to limit the observations of the Ulisse system at predetermined time intervals. However, self-reported estimates need to be adjusted using an appropriate over-reporting factor. Language: en