The endurance of the effects of the penalty point system in Spain three years after. Main influencing factors.

In this work we have used ARIMA time series models to analyse the contribution of the penalty point system, the most important legislative measure for driving licences, in reducing the number of fatalities over 24h on the roads in Spain during the study period (January 1995 to June 2009). In addition, because of this long period of analysis, other control variables were introduced to model the enactment of the Reform of the Penal Code in December 2007, together with other more specific effects needed to fit the model correctly. The ARIMA intervention models methodology combines the basic features of specific times series models: it controls the trend and seasonal variation in data that is present when modelling the structure through autoregressive and moving average parameters and allows for inserting step or impulse input variables for checking and evaluating the effects of deterministic measures, such as legislative changes which are the object of study in this work. This paper analyses the surveillance and control measures introduced in the periods before and after the implementation of the penalty point system and helps to partly explain its apparent endurance over time. The results show that the introduction of the penalty point system in Spain had a very positive effect in reducing the number of fatalities (over 24h) on the road, and that this effect has endured up to the present time. This success may be due to the continuing increase in surveillance measures and fines as well the significantly growing interest shown by the news media in road safety since the measures were introduced. All this has led to positive changes in driver behaviour. It is, therefore, a combination of three factors: the penalty point system, the gradual stepping up of surveillance measures and sanctions, and the publicity given to road safety issues in the mass media would appear to be the key to success. The absence of any of these three factors would have predictably led to a far less positive evolution of the accident rate on Spanish roads.

The influence of heavy goods vehicle traffic on accidents on different types of Spanish interurban roads.

This paper illustrates a methodology developed to analyze the influence of traffic conditions, i.e. volume and composition on accidents on different types of interurban roads in Spain, by applying negative binomial models. The annual average daily traffic was identified as the most important variable, followed by the percentage of heavy goods vehicles, and different covariate patterns were found for each road type. The analysis of hypothetical scenarios of the reduction of heavy goods vehicles in two of the most representative freight transportation corridors, combined with hypotheses of total daily traffic mean intensity variation, produced by the existence or absence of induced traffic gives rise to several scenarios. In all cases a reduction in the total number of accidents would occur as a result of the drop in the number of heavy goods transport vehicles, However the higher traffic intensity, resulting of the induction of other vehicular traffic, reduces the effects on the number of accidents on single carriageway road segments compared with high capacity roads, due to the increase in exposure. This type of analysis provides objective elements for evaluating policies that encourage modal shifts and road safety enhancements.