According to the traditional approach, when estimating changes in transportation policies, the household income level (in all its forms) is perceived as the proper explanatory variable for modeling population transportation preferences. However, it is acknowledged that accurate information about this variable is difficult to gather. In contrast, information about household car characteristics is relatively simple to collect. This article presents the hypothesis that a lifestyle variable, such as investment in mobility by car (IMC), is a viable parameter for estimating household members’ behavioral tendencies toward transportation, from both practical and conceptual reasons. This research proposes a simple methodology to infer the IMC using existing data sources, and presents mode choice model estimation results using the IMC both as an explanatory variable and as a segmentation variable. The segmentation of the population in three IMC categories (low, middle, and high) yielded significantly different models of the preference systems for the three segments. These findings show that IMC is a viable variable for market segmentation.