10: The RES Model by Road Type in France

After the focus of attention was shifted at the beginning of the 1990’s in France to monitoring short-term indicators in order to isolate a trend for local fluctuations (Bergel and al., 1995), a need is now felt for an “explanatory” monitoring of risk indicators at a disaggregate level in relation to their principal determinants, for anticipation/prediction purposes.

The choice of monthly periodicity, which is the product of a compromise between the variability and availability of existing data and that of the determinants-weather and time-of-year conditions, traffic flow or its substitutes (economic activity, prices, and network development), behavioural variables and road safety measures-position this approach mid-way between the modelling of daily fluctuations and the modelling of long-term trends.