The actions on road safety concerning the speed limits have been the subject of more than one hundred efficiency evaluations in term of victim and accident numbers reduction since 1966. These country scale evaluations led Elvik and al. to make meta-analyzes allowing them to establish a certain adequacy with so called power models in which the degree vary from 4 to 8 for the number of the victims. Thus, we are seeking through times series of victims number in Switzerland, France and Hungary, to assess the impact of actions on speed limits. Indeed, Switzerland in 1984 and 1985 has launched a campaign action on speed by decreasing the authorized speed limits on its roads, by 10km/h for the urban zones and motorways, by 20km/h for the rural roads; in 1990 France has lowered the speed limits in town to 50 km/h; on the contrary, Hungary has increased the speed limit by 10 km/h outside built-up areas. The most widespread methodology for efficiency evaluation uses Poissonnian models of the killed number in before/after plans. . It is proposed in this article to tackle the question of evaluation through the modeling of time series, thus taking into account the possible time. In recent decades, non-parametric methods have been experiencing a significant development in the theoretical field, enhancing the scientific rigour as for their implementation. Two parametric models, autoprojectif and with transfer function, and a nonparametric model are proposed. The model with transfer function allows a direct effect modelling by the use of a dummy variable to characterize the event. These models then allow us to assess the impact of the measure on speed by comparing the calculated values to observed ones. (A). For the covering abstract of the conference see ITRD E217780.
Abstract