Mobilization of organizations insures the implementation of a public policy. It is required to yield an effective intervention. The police organizations play this crucial role in the traffic safety field. Police organizations intervene through many different ways: law enforcement, prevention, educative interventions...These different missions constitute their mandate, entrusted by government. These missions and the means for intervening can evolve with the modifications of their environment. They can be also explained by internal and organizational constraints. In order to understand the implications of the environmental and organizational constraints relative to the evolution of interventions of police organisations, this paper mobilizes PORTER’s model of competition. A specific application is done for Sûreté du Québec.