The issue of immiserizing growth has been largely discussed in the literature since 1958. It describes a country context contending with high volume of exports relatively to its imports on the international market that benefits from high economic growth but losses in households’ welfare. This study aims to investigate the contribution of transport infrastructure to tackle immiserizing growth in developing countries, focusing on the Cameroon economy, a contending with a significant lack in the development of road transport infrastructure. Further, the study enriches the debate on the wider economic impacts, closely related to immiserizing growth. The loss of welfare is observed upstream to the investigations, as a response to the application of two types of fiscal policies: the import tariff and the capital income tax. Through a dynamic Computable General Equilibrium (CGE) model, the effect of road transport infrastructure is explored, using the externalities approach. This is an innovative methodology recently applied to access the economic impacts of infrastructure investment making a difference between productive and non-productive infrastructure investments. The findings reveal that productive transport infrastructure not only reduces the wider economic impact by improving households’ welfare but also enhances economic growth. A 10 percent increase in road transport infrastructure investment funded by import tariff leads to a welfare improvement of 1.94% and 1.66% in both short and long terms compared to respective losses of 0.58% and 0.15% if the generated financial funds are allocated in non-productive infrastructure such as monuments, defense etc. The similar tendency is observed for the capital income tax funding. Thus, policymakers are recommended to accentuate the road construction, in order to shorten the complex interplay between public decisions and households’ living conditions.