A NTUA Diploma Thesis titled “Cost Benefit Analysis of 30 km/h speed limit implementation in all EU cities” was recently presented by Gerasimos Balatsinos. To achieve this objective, a methodological framework consisting a statistical analysis of road crashes and a Cost–Benefit Analysis at a macroscopic level were developed. Initially, road crash data recorded within urban areas for the period 2016–2022 were collected for each EU Member State. Subsequently, the data was utilized to develop two logistic regression models, incorporating fixed and random effects. The results indicate that crash severity is primarily influenced by the type of transport mode, lighting conditions, and age, while other factors exhibit a smaller yet statistically significant effect. Furthermore, substantial variation is observed across EU countries in terms of baseline risk levels. The findings suggest that the implementation of a 30 km/h speed limit constitutes an economically feasible measure at the European level, yielding a positive Economic Net Present Value (ENPV) of approximately €18 billion. At the city level, the ENPV ranges from approximately €90 million (Paris) to €4.6 billion (London).