Abstract:The traffic situation in Nairobi presents a growing challenge to road user and workers. This leads to low productivity, retarded growth of GDP, Fatigues and stress related challenges to city dwellers. Most of the trips generated in the suburbs and beyond seem to be directed to or through the CBD of Nairobi. The study was carried out in Nairobi Central Business District (CBD).This study set out to investigate how traffic jams in Nairobi cause lost hours of work. The objective of the study was: to investigate population growth variables and how they affect road transport in Nairobi leading to lost man hours in traffic jams. This study focused on matatu mode of public transport in Nairobi and specifically registered SACCOS operating in Nairobi. This study was anchored on the Central Place Theory, Utility theory and the Theory of Urban Fabric. The study used the cross-sectional research design with a qualitative survey approach. A sample of 56 Matatu SACCOS operating in Nairobi was used for the study. Mixed methods were used in the analysis where, content analysis was used to analyze qualitative verbal responses while SPSS was used to analyze quantitative data. The sample was computed as a percentage of the total population where 30% was used. This study discussed the Matatu systems challenges and potential solutions focusing on the problem of lost hours of work due traffic congestion. The research concluded that there psychosocial effects of traffic congestion which included loss of revenue, wastage of fuel on traffic, fatigue, lawlessness, lonely families members due to absentism of other members, lack of mentored children among others. All these are the consequences of inadequate traffic management systems in the CBD of Nairobi.This study makes various suggestions concerning the future of Nairobi's public transport system and the future role of Matatus. It notes that some of the positive quality attributes of status such as the introduction of BRT and light trains should be taken into account in planning for the future. Key words: traffic, population, jams, congestion, transport, urban.