Efficient traffic enforcement requires a system characterized by regulations where metrology must have a significant role. It is important for competent authorities and manufacturers to have efficient measurement traceability within the framework of conformity assessment of instruments available on the market. Therefore a growing interest lies in the role of metrological decisions in conformity assessment, particularly where measurements are in support of safety and health, such as in road safety. This paper focuses on the role of Portuguese Legal Metrology in the field of road safety, it emphasizes the relevance of metrological control of some measuring instruments in the field of the National Program Strategic Plan for Road Safety, as a way to prevent and monitor the crash rate.