Transportation and communication are one of the main infrastructures of every country's economy, and nowadays, they are considered as one of the indicators of countries' development. Despite the high significance of road transport in the development of societies, the growth and expansion of the number of vehicles, road accidents and traffic fatalities and the high economic and social costs caused by them have challenged transport authorities and traffic experts. In developing countries, road accidents increase until they reach a certain threshold level of income, and then this rate declines. This relationship is similar to Kuznets bio-environmental hypothesis. In this study, the socio-economic factors affecting road accidents in the context of Kuznets bio-environmental hypothesis are examined. The results show that there is a significant inverted U-shaped relationship between the economic growth in Iran and road fatalities. Additionally, the results of estimating the country and provincial patterns indicate that in the provincial pattern, the variable of the number of cars, and in the country pattern, the variable of gross domestic product, has the most effect on accidents.
