Dynamics of Automobile Ownership under Rapid Growth

Little research has focused on how the factors that influence travel behavior change in rapidly developing and increasingly motorized cities. This paper examines household motor vehicle ownership and focuses on potential variations in the preferences revealed through vehicle choice models estimated for Santiago, Chile, in 1991 and 2001 and includes measures of relative location, subway proximity, residential density, and land use mix. The results indicate that preferences changed between 1991 and 2001 and suggest that as incomes rise and vehicle ownership becomes increasingly affordable, the apparent influence of demographic, land use, and other contextual variables changes. The results vary across land use and locational variables; most notably, the relationship between vehicle ownership and land use mix appears to weaken over time, whereas the effect of the distance to the central business district strengthens, and the effect of residential density varies in the apparent direction of change, depending on the vehicle ownership category. By 2001, proximity to the subway had an apparent effect on the household decision to own three or more vehicles. This research shows that although income and motorization rates rapidly increased in Santiago, certain elements of the built environment influenced household vehicle ownership, and these influences changed over time. Future research should focus on potential market segments, such as suburban versus urban; aim to control for self-selection regarding land use and locational characteristics; and better understand the implications for travel forecasting.