Multiplicative models of analysis : a description and the use in analysing accident ratios as a function of hourly traffic volume and road-surface skidding resistance.

Accident ratios are analysed with regard to the variables road surface skidding resistance and hourly traffic volume. It is concluded that the multiplicative model describes the data better than the additive model. Moreover that there is no interaction between skidding resistance and traffic volume in their effect on accident ratios. The pictures of the relation between accident ratios and both variables are shown and the statistics regarding the contribution of the variables.