The opinions expressed in the studies are those of the consultant and do not necessarily represent the position of the Commission.
From laws and policy, to increased enforcement, to social benefits
Yannis et al.  describe the hierarchy of road safety enforcement. The legal and organizational framework enabling police enforcement provides the foundation for the actual policing operations. Such a framework will result in well-planned, intensified police controls on selected locations of the road network, resulting in an increase in the perceived risk of apprehension. As a result violation rates will decrease. Changes in road user behaviour will result in less traffic crashes and less traffic victims, and in reduced monetary costs for society (social benefits). The figure below describes this ideal scenario.
Figure 1: The hierarchy of road safety enforcement. Source: Yannis et al. (2004)
To maximize the road safety effects, traffic law enforcement should first and foremost prevent violations that are proven to be related with the number or severity of crashes.