1: Multiple Levels, Damages, Forms, Movements and Variables in Road Accident Models

The first part of this book contains a family of six models that explain the Demand for Road use, Accidents and their Gravity (DRAG), sharing a structure, use of flexible form regression analysis, calibration with monthly time series data defined over a country or region, and the establishment of a reference set of documented results. The purpose of this chapter is to introduce their common approach in terms of these four components that definea “Modelling Quartet” for any model: formulation, quantification of effects, data type and the expression of results. The focus on the six members of the family will also initiate to the two models presented in the second part of the book and to the algorithms found in the third part.