Road safety is a complex process that not only depends on technical and environmental improvements, but in a major part from human factors. In this sense, recent empirical studies have remarked the need to study the interaction between subject and laws, at the glance of several elements preceding road behavior. This is the case of attitudes, opinions and perceptions in the field of road safety, factors that influence the interaction with issues such as traffic rules, police supervision, penalties and justice in traffic. The objective of this study was to describe the self-rated knowledge and perceptions regarding traffic norms and its interaction with road safety among drivers. For this study, a sample of 1100 Spanish drivers was obtained from a national sampling process. The results showed that the clear majority of drivers consider they know in a sufficient manner the traffic norms, and consider them as effective. Concerning police supervision, almost 70% of them consider that it is effective, but generally assumes that traffic agents prefer to be located in strategical places to catch offenders, rather than in really dangerous places. Regarding sanctions, drivers conceived the punishment to road offenders principally as educational and tax-collection measures. Finally, the general assessment of justice in traffic provided by Spanish drivers has shown a regular-low valuation degree. The obtained results invite to discuss about the interaction between traffic norms and road user, with the aim of promoting a positive law enforcement as a manner to build road safety culture.