Well planned and executed urban mobility policies are essential for economic, social, and environmental development. Cities in developing countries, in particular, face serious problems involving infrastructure, traffic congestion, and services accessibility. These factors, made worse by poor planning, lead to social inequality. This paper conducts a multidimensional analysis of how travel times and the related opportunity costs lead to transport-related social exclusion (TRSE) situations in Ajegunle, in Lagos, Nigeria. Our contribution to the literature is to extend and quantify the TRSE framework in the case of a low-income community in a developing country. The methodology applies an interdisciplinary research design that uses open-access remote-sensing and route planning web applications (Google Maps, Google Earth, and Lara.ng) and a critical literature review, embedded in a TRSE framework. Thereby we obtain the difference between the estimated and the ideal travel times that residents of this community take to reach locations offering five different services – education, work, shopping, leisure, and health – distributed in seven locations across the city. Based on the difference between the estimated and ideal travel times, which on average is between half an hour and two hours, we calculate the opportunity cost based on local living wages as benchmark, which results in an average between 7.6% and 27.4% of the daily wages. This concept captures a temporal and spatial valuation, expressed in monetary terms, of the impact of an inadequate public transport system on poorer residents' everyday lives. This analysis using the TRSE framework shows that poor public transport, and consequently high opportunity costs, translates into social exclusion in this low-income community. Finally, we recommend a set of practical transport, urban-planning, and social policies that can remedy this predicament.