RES, a Network Disaggregate Model for Road Risk
R Bergel, INRETS, FR
This paper deals with a model for road risk, developped for the French Road Safety Observatory, under two contracts concluded between the Ministry of Transportation, the University and Inrets.
According to the Drag-type approach, time series modelling including exogenous variables has been applied on a monthly basis to the triangle 'risk exposure/risk/gravity', for the period 1975-1999.
We mainly describe the model related to the monthly number of injury accidents and fatalities,agregated on the whole territory, and disagregated by road network (main roads, motorways, secondary roads, urban network).
The exogenous variables measure risk exposure, the climatic conditions and the calendar configuration.
The elasticity values, of the numbers of injury accidents and fatalities with respect to these determinants are discussed, and compared with the values obtained in the litterature.
We give examples,of the road safety indicators evolution over the period, and discuss the model's performance.
Special attention is paid to the climate influence. On both main roads and motorways, the two networks on which the traffic volume is measured, the climate effect is separated in two parts: a direct effet, due to the drivers behaviours modification, and an indirect effect through risk exposure.The results obtained, related to temperature, rainfall and frost, are discussed.
Association for European Transport