Transport is one of the most important activities, a turning point of the modern world, because it connects people and cities in various ways, from modern buses and trams to modern trains, and in this way contributes to the better development of cities and society in general, helping people to fluctuate daily wherever they want without owning transport means. But considering the accelerated development of traffic, there are also numerous schortcomings that negatively affect society as a whole,and traffic is seen as a negative factor that primarily pollutes the environment with means that are increasing every day, so some countries have decided to change their policies so as they would protect their cities from the negative impact of trafficm which has been quite large in recent years. In this thesis, an attempt is therefore made to clarify the most important terms related to traffic and its impact on cities through the subject of the work, which refers to the importance of traffic in cities. We also try to present to the reader its importance in the development of cities, but also to acquaint him with some of the negativity associated with this same development. The thesis is divided into seven units that aim to deschribe the functions of the city, types of traffic, traffic infrastructure, communal economy ecology in traffic and the impact of traffic on the development of the city. Particular attention is paid to the Transport Development Strategy of the Republic of Croatia. Writing the thesis led to many new insights and ineresting things, and it was observed that oublic tranpsort is of great benefit to citizens and that certain cities are developing more and more thanks to well-developed infrastructure.