Enterprises often embed decision-making processes in procedures in order to address issues in all cases. However, procedures often lead to sub-optimal solutions for any specific decision. As a consequence, each actor develops the practice of addressing decision making in a specific context. Actors contextualize decision making when enterprises are obliged to decontextualize decision making to limit the number of procedures and cover whole classes of decision-making processes by generalization. Practice modeling is not easy because there are as many practices as contexts of occurrence. This chapter proposes a way to deal effectively with practices. Based on a conceptual framework for dealing with context, we present a context-based representation formalism for modeling decision making and its realization by actors. This formalism is called contextual graphs and is discussed using the example of modeling car drivers’ behaviors.