The European Commission with the active contribution of NTUA, SWOV and KFV has published at the European Road Safety Observatory, the Traffic law Enforcement Thematic Report which defines Traffic Law Enforcement (TLE)  as the entire penal procedure designed to persuade road users to abide by traffic laws and regulations through threat of detection of violation and the imposition of a penalty or other sanction. In a safe road system, both general and targeted TLE are required to limit the occurrence of the safety-critical violations. Within the safe system approach TLE is best combined with other measures to reduce violations. Furthermore, the main types of TLE can be distinguished along three main dimensions: automatic versus manned controls, stationary versus mobile controls, and visible/conspicuous versus less visible/hidden controls. Although enforcement can improve road safety, it remains a challenge to maintain and optimize the effects of TLE.