Income, or the lack of it, influences household transportation decisions and the ways in which individuals travel. Low-income households are less likely to own cars and more likely to travel by modes other than the automobile. Less is known, however, about the specific determinants of travel among the poor, which was the purpose of this analysis. This study used data from the 2009 National Household Travel Survey to examine the relationship between income and automobile ownership and the role of automobile ownership in explaining person miles traveled. An analysis was then made of whether these determinants varied by income group. The results indicated that low-income adults rapidly convert rising income into additional mobility at faster rates than higher-income adults. Further, automobile ownership increases person miles traveled for all adults; however, it is particularly influential in increasing the travel of low-income adults. Households accrue greater marginal benefits by moving from zero to one vehicle than by purchasing additional vehicles when they already own one or more. These findings underscore the importance of automobile ownership to the mobility of low-income households and suggest an important role for policy in facilitating low-income auto ownership.