With regard to laws on smoking, it is seen that sales of cigarettes declined considerably between 2000 and 2015. Graph 2 shows that the first intervention (Law 28/2005) did not have a significant effect on the change in the series level, registering only a change in tendency, which acquires a negative slope: cigarette sales start to fall. The entry into force of Law 42/2010 causes a change in series level, which represents a sharp fall of 9.41% in cigarette sales, but without significant changes in the evolution of the tendency.

With the aim of ordering the effects of the main variables influencing the variation in cigarette sales by importance, graph 3 shows the weight or percentage of the explanation for each of these in the variability of sales over the course of the period analysed. The most important variable corresponds to the entry into force of Law 42/2010, which explains 16.55% of the variation in sales, whereas the first intervention (Law 28/2005) explains only 6.81% of the change. Next, changes in the minimum tax provide an explanation for 14.85%, followed by seasonality and tendencies of the series, at 14.16% and 13.93% respectively. It should not be forgotten that cigarette sales are highly seasonal, with significant peaks in December and in the summer months, due to greater leisure time and sales to tourists. Also, the higher the tax burden the higher the price, a fact which, combined with a reduction in disposable income, has a negative effect on cigarette sales.

In relation with the possible effect of road safety laws over the course of the period analysed, it is seen that mortality due to road traffic accidents has declined year after year. In accordance with the adjustment shown in graph 4, the entry into force of the driving licence points system does not significantly affect the behaviour of the series, neither accelerating nor slowing down the reduction in mortality; the changes appear two years later. The reform of the Penal Code that entered into force in December 2007 caused a sharp reduction, with a change of level which, deducted from the tendency of the series itself, stands at 14% of mortality due to road traffic accidents.

In the road safety model, the variable analysed (deaths due to road traffic accidents) is adjusted according to number of vehicles registered; furthermore, the following control variables are incorporated into the series tendency: seasonal variations and changes in fuel prices and in the average disposable income of Spanish families.
The percentage of explanation of each variable is shown in graph 5. The most important variable, with 24.63% of explanation of the variance in the mortality rate due to road traffic accidents, is the series tendency, an effect that is confused with the entry into force of the licence points system. The Spanish population appears to be increasingly aware regarding traffic and road safety issues, which is expressed as a continual decline in mortality. However, there continue to be deaths, mainly in the summer months, due to the increase in the number of road journeys. Seasonality explains 17.63% of the changes in the mortality rate. Also bearing relation to the volume of road journeys are changes in fuel prices and in family incomes. The higher the price of fuel or the lower the family income, the lower the number of road journeys taken. The changes in these two variables explain 10.58% and 10.26%, respectively, of the variance. Finally, the reform of the Penal Code of 2007 explains 13.34% of the fall in mortality due to road traffic accidents in the period analysed.
