Among winter period, the climatic conditions in the state of Lleida, where L4 sector is located, cause an important number of days with northern or north-western wind which maintains a very low temperatures with a dry road. Our experience allows estimate that the permanence of the salt on the road is higher in dry than in wet road conditions, especially when we use brine for anti-icing treatments. But, the consequence of a hypothetic accident, where the driver denounces ice on the road when we have not realize the pertinent treatment, promotes us to carry out anti-icing treatments to defend ourselves against possible claims and not because they were really necessary. These unnecessary treatments became an important increase of the economic cost of the infrastructure's maintenance and a higher impact on the environment. This paper expects to provide the trends about the taken salinity measurements reveal, under various conditions (e.g. traffic, different pavements types and different treatment types). Decision makers might use these trends as a tool for understanding the connection between the different factors that are involved about the amount of residual salt on the dry road. In future seasons, we could get better relationship between the residual salt and the traffic conditions. [ABSTRACT FROM AUTHOR]