First roads were built to enhance and simplify traffic connections and were mostly used to create trade routes across the mountain covered areas. In the beginning, they were suitable only for the cargo transport via animals. As time and quality of the roads progressed, wheelbased transporting devices emerged as the dominant traffic mode, benefiting the trade exchange. The roads were mostly macadam based, whereas the modernisation period brought upon the greater need for adequate traffic connectivity and subsequently the expansion and further upgrade of the roads. With the invention of internal combustion engines and by building more modern roads in the last few hundred years, a giant leap in the development and modernisation of roads occurred. However, considering the great number of vehicles per city, roads have become relatively tight, while noise and harmful particles resulting from the internal combustion engines have become a great danger to human health. If oil consumption remains at the same yearly rate, it is estimated that in 50 years most of the natural oil reserve will be depleted. Therefore, leading world experts and scientists have concluded that a change must occur. Thus began the manufacturing process of alternate fuel vehicles. In this Bachelor Thesis entitled Differentiation of road traffic, dynamic forces and hybrid vehicles, road traffic and vehicles development in Republic of Croatia and the world has been investigated. Considering the favourable geographic position, Republic of Croatia contains high number of roads and highways relative to the surface area and population of the country. Furthermore, around two million road vehicles are registered in Croatia, which is the cause for turning towards the alternative fuels. Newton’s law of motion, dynamic force reactions, pull forces, resistance and forces occurring during the vehicle start-up are discussed within this thesis. Special attention is dedicated to hybrid vehicles manufacturing and development technology. Maintenance, safety, reliability and life cycle of the hybrid vehicles is discussed in detail.