The objective of this Diploma Thesis is to investigate the long–term correlation between road accidents and weather conditions in European cities. On that purpose, a database containing average monthly temperature and precipitation data for every city – as well as the monthly number of road accidents for the period 1991-2017 was developed. The cities were divided into two groups: southern and northern cities. Linear Mixed Models were developed for the total time period, as well as for the periods of 1991-2005 and 2006-2017, indicatively before and after intensification of climate change. Moreover, another model correlating the GDP per capita with temperature and road accidents was developed. The application of the models concluded that increase of precipitation and temperature results at increase of road accidents. For the group of south cities, the impact of weather conditions in road accidents is found more severe. For each time period, the rain has a negative impact on accidents, although their correlation is positive. Furthermore, temperature increase due to climate change slows down the improvement of road safety.