The mobility of people and goods in urban areas depends on the availability of transport infrastructure. In urban areas, particularly in cities of underdeveloped countries, the unprecedented increase in population has led to an increasingly high demand for transport infrastructure. The urban means of transport used for the mobility of people and goods are taxis, motorcycle taxis, private cars, etc. In addition, coaches, minibuses, buses, heavy goods vehicles, etc. are used for transit transport. The high demand for means of transport linked to urban population growth has led to an increase in urban traffic, resulting in congestion of urban roads. Traffic jams in cities of poor countries are amplified by the poor condition and narrowness of communication routes, the obstruction of roadways by economic activities and various waste, the absence of traffic lights at busy intersections, etc. Road congestion has enormous consequences for road users. The objective of this article is to show how mobility is the cause of road congestion in the Yaoundé IV district. The methodology adopted is based on literature review, participant observation, semi-structured interviews, GPS surveys, questionnaire surveys, etc. The documentary research consisted of collecting a certain amount of qualitative data on the subject by consulting various documents on the internet and certain works (dissertations, theses, etc.) on this theme. In addition, the other methods used allowed us to collect quantitative and qualitative data on the means of transport, the factors amplifying congestion and its consequences in the district commune of Yaoundé IV. The results obtained indicate that the means of transport used in the study area for the mobility of people and goods are, among others, taxis, motorcycle taxis, personal cars, etc. It emerges from the field investigations that the most used means of transport in the district commune of Yaoundé IV is the city taxi because 44% of respondents use this me