We propose a modeling of decision making that offers a unified framework for what are generally contrasted—procedure versus practice, task versus activity, logic of functioning versus logic of use, and allows the identification of two types of contextualization. Human behavior often is described on policy, strategy, tactic and operation levels. From the upper level (policy) to the lower (operation), the decision making process goes through two successive contextualizations. At the first level, decision making has a fix part (policy and strategy) and a dynamic part (tactic and operation) at the second level. Real-time aspects of a decision making are on the dynamic part, i.e. in strong connection with the context in which an actor makes his decision. A contextual methodology has been proposed in road safety domain (in which the car driver is continuously in situation of real-time decision making) and now used in another application in Open Source domain.