in Sub-Saharan African cities

Estimating the incomes of individuals and households is particularly important in the cities of Sub-Saharan Africa where the use of motorized transport is expensive and there are many sociospatial inequalities with regard to access to urban amenities. This paper sets out to answer two questions. First, how can data on individuals ’ incomes be collected as accurately as possible?, and second, what benefits can we expect with regard to the analysis of travel and inequalities from an improvement in the quality of income data? For this purpose, the methods used in three surveys have been compared: one living conditions survey and two household travel surveys. The results show that detailed collection of income data from each individual according to its source markedly reduces the non-response rate and improves the accuracy of the total income assessment. They also show that inequalities with regard to the travel indicators for mechanized trips and the amounts of money spent appear to be considerably greater when income is collected in a precise and individualized manner. Detailed collection of individual income data is thus helpful for studying individual determinants of travel and makes it possible to take better account of equity issues with regard to access to transportation and the city