The aim of this dissertation is the analysis of the acceptance and the benefits of reducing speed limits from 50km/h to 30km/h in Athens. For this reason, a special questionnaire was created which was answered by 408 inhabitants based on the method of the declared preference for various hypothetical scenarios of time, fuel consumption and the possibility of a road accident. Respondents were asked to choose between three alternative proposals: a) Speed limit reduction to 30km/h in the entire urban network except the main arteries b) Speed limit reduction to 30km/h in the entire urban network and c) No speed reduction. Subsequently, two binomial regression logistic models and three polynomial regression logistic models were developed. From the combined models, it emerged that the variables that affect the user’s choice to choose one of the above three alternatives are the increase in travel time, the value of the role of speed for them to cause an accident, the number of the accidents in which they had been part of, their driving habits and other demographics of the drivers. At the same time, the viability control of the implementation of this measure was implemented through the cost-benefit analysis method. The analysis calculated the benefit from reducing accidents to minor injuries, severely injured, deaths, the costs incurred due to the increase in travel time and the benefit from reducing fuel consumption and environmental impact (CO2, NOx, PM emissions). Finally, the implementation of the speed limit reduction measure at 30 km/h was deemed economically viable and worth of implementing.